build: embed images with #embed, keep everything generated in build/

the cores take their genome in with c23 #embed through src/core/genome.h,
so images are plain little-endian word files (genome.bin) instead of
generated c headers. zc0 writes that format, mkgenome checks an image
against its map and shows a compiler's diagnostics when it gets them,
and the javascript vm and the editor's vm host read the same files.
src/tools/findcc.sh picks a compiler with #embed (clang 19 or gcc 15).

zc gets an embed declaration, embed "file" as [type] name, for globals
and locals: a byte string by default, char*, numbers read little-endian,
and arrays of numbers. the compiler and language server carry their
library and source texts through it, so embed.sh and the text it
spliced into compiler.zc are gone.

make writes executables to build/bin, the default map to build/core/map,
the web page to build/web and the extension staging to build/vsix, and
the genome now rebuilds when its sources change. the test suite lays
out its own map and bootstrap and reads nothing from build/.

also: rt.put_s of a byte string in zc0 images, retained function
sources no longer count as live objects, a missing include no longer
cascades into undefined-name errors, consecutive comment lines join
into one hover paragraph, and stale test fixtures follow the include
format.

79 files changed, 1472 insertions, 1142 deletions

diff --git a/.gitignore b/.gitignore
index d79798a..904cd31 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,15 +1,7 @@
-# build output
-bin/
+# everything built or generated lives in build/ (make clean removes it)
+/build/
+
+# stray objects and executables from building by hand
 *.o
 *.obj
 *.exe
-
-# built programs
-/bin/
-/build/
-/src/web/zc.wasm
-
-# the editor's packaged server: layout, vm and language-server image, plus the
-# wasm server. `make vsix` stages it into editors/vscode/server/ only while it
-# packages, so nothing built is kept in the tree.
-/editors/vscode/server/
diff --git a/Makefile b/Makefile
index 6a3898d..7f8f3f2 100644
--- a/Makefile
+++ b/Makefile
@@ -1,27 +1,30 @@
 # tinyvm and zc. `make` builds the tools, the interpreter, the microcore and the
-# language server into bin/. nothing built is kept in the tree.
+# language server into build/bin/. everything built or generated goes under
+# build/; the tree holds sources only, and `make clean` (rm -rf build) returns it
+# to a fresh checkout.
 #
 #   make                 everything below that is a program
 #   make test            the whole suite (tests/test.sh)
 #   make check           the minimal suite, for iterating (tests/test.sh -q)
 #   make test JOBS=4     the same, four sections at a time
-#   make genome          rebuild build/core/genome.h from src/ and check the fixpoint
-#   make lsp             bin/zclsp, the language server
-#   make web             src/web/zc.wasm (needs clang with the wasm32 target)
-#   make js              build/js/genome.json and the vm, for the javascript vm
+#   make genome          build/core/genome.bin from src/, with the fixpoint check
+#   make lsp             build/bin/zclsp, the language server
+#   make web             build/web/: the page, its script and zc.wasm
+#   make js              build/js/: the javascript vm, its layout and genome
 #   make run PROG=examples/hello.zc
 #                        compile one program into a run-only image on a memory
 #                        map sized to it (src/tools/automap.sh) -> build/run/zymr
 #   make vsix            the vscode extension, server and all
-#   make clean           remove bin/ and build/ and the web build
+#   make clean           remove build/
 #
-# nothing built is kept in the tree: the genome, the javascript vm and its
-# layout, and the packed editor server all land in build/ (the web build keeps
-# its historical src/web/zc.wasm path because the page loads it by name).
-#
-# CC picks the compiler (cc by default; clang works too).
+# the cores take their genome in with c23 #embed (src/core/genome.h), so CC has
+# to be clang 19 or gcc 15 or later. src/tools/findcc.sh picks one when CC is
+# not given on the command line or in the environment.
 
-CC     ?= cc
+ifeq ($(origin CC),default)
+  CC := $(shell sh src/tools/findcc.sh || echo cc)
+endif
+export CC
 CFLAGS ?= -O2 -w -fwrapv
 ifeq ($(OS),Windows_NT)
   EXE := .exe
@@ -35,99 +38,105 @@ else
   MICRO_THREADS := -DZY_THREADS
 endif
 
-BIN := bin
 B   := build
+BIN := $(B)/bin
 JS  := $(B)/js
-# the hand-written core headers, then the generated genome beside them
-COREINC := -Isrc/core -I$(B)/core
-# the sources the compiler genome is built from
+WEB := $(B)/web
+# the default memory map, generated from the const blocks in the zc sources
+MAP := $(B)/core/map
+# hand-written core headers, the generated map, and where #embed finds the genome image
+COREINC := -Isrc/core -I$(MAP) --embed-dir=$(B)/core
+CORE_H := src/core/genome.h src/core/fops.h src/core/bops.h src/core/stack.h $(MAP)/memmap.h
+# the sources the compiler genome is built from, and the files it embeds
 ZC_SRC := src/runtime/rt.zc src/core/core.zc src/compiler/compiler.zc
+ZC_DEPS := $(ZC_SRC) src/lib/std.zc src/lib/icon.zc src/tools/build.zc
 
 TOOLS := $(BIN)/zc0$(EXE) $(BIN)/mkgenome$(EXE) $(BIN)/genmap$(EXE)
 PROGS := $(BIN)/zy$(EXE) $(BIN)/zym$(EXE) $(BIN)/zclsp$(EXE)
 
 all: $(TOOLS) $(PROGS)
 
-$(BIN) $(B):
+$(BIN):
 	mkdir -p $@
 
-$(BIN)/zc0$(EXE): src/tools/zc0.c src/core/memmap.h src/core/fops.h src/core/bops.h | $(BIN)
-	$(CC) -O1 -w -fwrapv src/tools/zc0.c -Isrc/core -o $@
-$(BIN)/mkgenome$(EXE): src/tools/mkgenome.c src/core/memmap.h | $(BIN)
-	$(CC) -O1 -w -fwrapv src/tools/mkgenome.c -Isrc/core -o $@
+# genmap needs no map of its own; everything else is built against the one it writes
 $(BIN)/genmap$(EXE): src/tools/genmap.c | $(BIN)
-	$(CC) $(CFLAGS) src/tools/genmap.c -Isrc/core -o $@
+	$(CC) $(CFLAGS) src/tools/genmap.c -o $@
+$(MAP)/memmap.h: $(BIN)/genmap$(EXE) src/runtime/rt.zc src/compiler/compiler.zc
+	mkdir -p $(B)/core
+	$(BIN)/genmap$(EXE) --preset default --check -o $(MAP) >$(B)/core/genmap.log 2>&1 || { cat $(B)/core/genmap.log; exit 1; }
+$(BIN)/zc0$(EXE): src/tools/zc0.c src/core/fops.h src/core/bops.h $(MAP)/memmap.h | $(BIN)
+	$(CC) -O1 -w -fwrapv src/tools/zc0.c -Isrc/core -I$(MAP) -o $@
+$(BIN)/mkgenome$(EXE): src/tools/mkgenome.c $(MAP)/memmap.h | $(BIN)
+	$(CC) -O1 -w -fwrapv src/tools/mkgenome.c -I$(MAP) -o $@
+
+# bootstrap: zc0 compiles the compiler to g0, g0 compiles it to g1, g1 to g2.
+# g1 and g2 must be identical (the fixpoint), and g1 becomes build/core/genome.bin.
+# each stage's core embeds the image beside it, so no stage reads another's.
+genome: $(B)/core/genome.bin
+$(B)/core/genome.bin: $(ZC_DEPS) $(BIN)/zc0$(EXE) $(BIN)/mkgenome$(EXE) src/core/core.c $(IO) $(CORE_H)
+	mkdir -p $(B)/s0 $(B)/s1 $(B)/core
+	cat $(ZC_SRC) | $(BIN)/zc0$(EXE) > $(B)/s0/g0.bin
+	$(BIN)/mkgenome$(EXE) < $(B)/s0/g0.bin > $(B)/s0/genome.bin
+	$(CC) $(CFLAGS) -DJTYPE=int src/core/core.c $(IO) -Isrc/core -I$(MAP) --embed-dir=$(B)/s0 -o $(B)/s0/zy0$(EXE)
+	(cat src/tools/build.zc; printf '`'; cat $(ZC_SRC)) | $(B)/s0/zy0$(EXE) > $(B)/s1/g1.bin
+	$(BIN)/mkgenome$(EXE) < $(B)/s1/g1.bin > $(B)/s1/genome.bin
+	$(CC) $(CFLAGS) -DJTYPE=int src/core/core.c $(IO) -Isrc/core -I$(MAP) --embed-dir=$(B)/s1 -o $(B)/s1/zy1$(EXE)
+	(cat src/tools/build.zc; printf '`'; cat $(ZC_SRC)) | $(B)/s1/zy1$(EXE) > $(B)/s1/g2.bin
+	cmp $(B)/s1/g1.bin $(B)/s1/g2.bin
+	cp $(B)/s1/genome.bin $@
+	@echo "fixpoint: $$(( $$(wc -c < $@) / 8 )) words, $@ updated"
 
 # the interpreter: the vm core with the compiler genome inside
-$(BIN)/zy$(EXE): src/core/core.c $(IO) $(B)/core/genome.h src/core/memmap.h src/core/fops.h src/core/bops.h src/core/stack.h | $(BIN)
+$(BIN)/zy$(EXE): src/core/core.c $(IO) $(B)/core/genome.bin $(CORE_H) | $(BIN)
 	$(CC) $(CFLAGS) -DJTYPE=int src/core/core.c $(IO) $(COREINC) -o $@
 # the portable microcore
-$(BIN)/zym$(EXE): src/micro/micro.c src/micro/micro_port.h $(PORT) $(B)/core/genome.h src/core/memmap.h src/core/fops.h src/core/bops.h src/core/stack.h | $(BIN)
+$(BIN)/zym$(EXE): src/micro/micro.c src/micro/micro_port.h $(PORT) $(B)/core/genome.bin $(CORE_H) | $(BIN)
 	$(CC) $(CFLAGS) $(MICRO_THREADS) src/micro/micro.c $(PORT) $(COREINC) -Isrc/micro -o $@
 
 # the language server is the compiler in check mode plus src/lsp/server.zc, on a map
 # sized to it
+LSP_DEPS := src/core/core.c src/core/io_linux.c $(filter-out $(MAP)/memmap.h,$(CORE_H)) $(ZC_DEPS) src/lsp/server.zc \
+	src/tools/zc0.c src/tools/genmap.c src/tools/mkgenome.c src/tools/automap.sh src/tools/mklsp.sh
 lsp: $(BIN)/zclsp$(EXE)
-$(BIN)/zclsp$(EXE): src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/memmap.h src/runtime/rt.zc src/core/core.zc src/compiler/compiler.zc src/lsp/server.zc src/lib/std.zc src/lib/icon.zc src/tools/embed.sh src/tools/zc0.c src/tools/genmap.c src/tools/automap.sh src/tools/mklsp.sh | $(BIN)
-	CC="$(CC)" bash src/tools/mklsp.sh $(B)/lsp
+$(BIN)/zclsp$(EXE): $(LSP_DEPS) | $(BIN)
+	bash src/tools/mklsp.sh $(B)/lsp
 	cp $(B)/lsp/zclsp$(EXE) $@
 
-src/compiler/compiler.zc: src/lib/std.zc src/lib/icon.zc src/tools/embed.sh
-	bash src/tools/embed.sh all
-
-# bootstrap: zc0 compiles the compiler to g0, g0 compiles it to g1, g1 to g2.
-# g1 and g2 must be identical (the fixpoint), and g1 becomes build/core/genome.h.
-# run this by hand after editing a .zc source; `make check` reports a stale genome.
-genome: $(BIN)/zc0$(EXE) $(BIN)/mkgenome$(EXE) src/compiler/compiler.zc | $(B)
-	mkdir -p $(B)/s0 $(B)/s1 $(B)/core
-	cp src/core/core.c $(IO) src/core/memmap.h src/core/fops.h src/core/bops.h src/core/stack.h $(B)/s0/
-	cp src/core/core.c $(IO) src/core/memmap.h src/core/fops.h src/core/bops.h src/core/stack.h $(B)/s1/
-	cat $(ZC_SRC) | $(BIN)/zc0$(EXE) > $(B)/s0/genome.h
-	$(CC) $(CFLAGS) -DJTYPE=int $(B)/s0/core.c $(B)/s0/$(notdir $(IO)) -o $(B)/zy0$(EXE)
-	(cat src/tools/build.zc; printf '`'; cat $(ZC_SRC)) | $(B)/zy0$(EXE) > $(B)/g1.bin
-	$(BIN)/mkgenome$(EXE) < $(B)/g1.bin > $(B)/s1/genome.h
-	$(CC) $(CFLAGS) -DJTYPE=int $(B)/s1/core.c $(B)/s1/$(notdir $(IO)) -o $(B)/zy1$(EXE)
-	(cat src/tools/build.zc; printf '`'; cat $(ZC_SRC)) | $(B)/zy1$(EXE) > $(B)/g2.bin
-	cmp $(B)/g1.bin $(B)/g2.bin
-	cp $(B)/s1/genome.h $(B)/core/genome.h
-	@echo "fixpoint: $$(( $$(wc -c < $(B)/g1.bin) / 8 )) words, $(B)/core/genome.h updated"
-
-# a fresh clone has no genome, so bootstrap one on demand. it is deliberately
-# not rebuilt from source dependencies: the fixpoint run is expensive, and
-# `make genome` is the explicit way to refresh it after editing a .zc file.
-$(B)/core/genome.h:
-	$(MAKE) genome
-
-js: $(JS)/genome.json $(JS)/layout.js $(JS)/tinyvm.js
+# the javascript vm: tinyvm.js loads genome.bin from beside itself
+js: $(JS)/tinyvm.js $(JS)/layout.js $(JS)/genome.bin
 $(JS):
 	mkdir -p $@
-$(JS)/genome.json: $(B)/core/genome.h src/core/memmap.h src/js/extract_genome.js src/js/mapvalues.js | $(JS)
-	node src/js/extract_genome.js
-$(JS)/layout.ts $(JS)/layout.js: $(JS)/genome.json
-	@test -f $@ || node src/js/extract_genome.js
+$(JS)/genome.bin: $(B)/core/genome.bin | $(JS)
+	cp $< $@
+$(JS)/layout.js: $(MAP)/memmap.h src/js/mklayout.js src/js/mapvalues.js | $(JS)
+	node src/js/mklayout.js --map $(MAP)/memmap.h --out $(JS)
 $(JS)/tinyvm.js: src/js/tinyvm.ts src/js/layout.d.ts | $(JS)
 	tsc src/js/tinyvm.ts --target es2020 --lib es2020,dom --module commonjs --outDir $(JS)
 
 # the language server image for the javascript vm, and the wasm server
-lspimage: $(JS)/lsp.json
-$(JS)/lsp.json: $(BIN)/zclsp$(EXE) src/js/extract_lsp.js src/js/mapvalues.js | $(JS)
+lspimage: $(JS)/lsp.bin
+$(JS)/lsp.bin: $(BIN)/zclsp$(EXE) src/js/extract_lsp.js src/js/mapvalues.js | $(JS)
 	node src/js/extract_lsp.js
 
 # the vscode extension, with the server and its image inside it
-vsix: | $(B)
+vsix:
 	bash src/tools/mkvsix.sh
 
-web: src/web/zc.wasm
-src/web/zc.wasm: src/micro/micro.c src/micro/micro_port.h src/web/port_wasm.c src/web/build.sh $(B)/core/genome.h src/core/memmap.h src/core/fops.h src/core/bops.h src/core/stack.h
+# the browser compiler: the page and its loader beside the wasm build
+web: $(WEB)/zc.wasm $(WEB)/index.html $(WEB)/zc.js
+$(WEB)/zc.wasm: src/micro/micro.c src/micro/micro_port.h src/web/port_wasm.c src/web/build.sh $(B)/core/genome.bin $(CORE_H)
 	bash src/web/build.sh $@
+$(WEB)/index.html $(WEB)/zc.js: $(WEB)/%: src/web/%
+	mkdir -p $(WEB)
+	cp $< $@
 
 # one program as a run-only image: the runtime, the program, and a map exactly
 # big enough for them
-run: | $(B)
+run:
 	@test -n "$(PROG)" || { echo "make run PROG=examples/hello.zc"; exit 2; }
 	bash src/tools/automap.sh run $(B)/run src/runtime/run.zc $(PROG)
-	cp src/micro/micro.c src/micro/micro_port.h $(PORT) src/core/fops.h src/core/bops.h src/core/stack.h $(B)/run/
-	$(CC) $(CFLAGS) $(MICRO_THREADS) $(B)/run/micro.c $(B)/run/$(notdir $(PORT)) -I$(B)/run -o $(B)/run/zymr$(EXE)
+	$(CC) $(CFLAGS) $(MICRO_THREADS) src/micro/micro.c $(PORT) -Isrc/core -Isrc/micro -I$(B)/run --embed-dir=$(B)/run -o $(B)/run/zymr$(EXE)
 	@echo "built $(B)/run/zymr$(EXE)"
 
 # JOBS sets how many sections run at once: make test JOBS=4
@@ -139,6 +148,6 @@ check:
 	bash tests/test.sh -q -j $(or $(JOBS),2)
 
 clean:
-	rm -rf $(BIN) $(B) src/web/zc.wasm
+	rm -rf $(B)
 
 .PHONY: all lsp genome js lspimage vsix web run test check clean
diff --git a/editors/vscode/client/extension.js b/editors/vscode/client/extension.js
index 3846eca..cd497d8 100644
--- a/editors/vscode/client/extension.js
+++ b/editors/vscode/client/extension.js
@@ -185,7 +185,7 @@ function shortKey(key) {
 function serverStampFor(bin) {
     if (bin) return fileStamp(bin);
     const dir = path.join(__dirname, '..', 'server');
-    return sha256(['lsp.wasm', 'lsp.json', 'tinyvm.js'].map(f => fileStamp(path.join(dir, f))).join(','));
+    return sha256(['lsp.wasm', 'lsp.json', 'lsp.bin', 'tinyvm.js'].map(f => fileStamp(path.join(dir, f))).join(','));
 }
 
 // the key of a document as it is now, and what it reads (for checking it again when one of those changes)
diff --git a/editors/vscode/client/vmproc.js b/editors/vscode/client/vmproc.js
index 8ce8c52..6b57554 100644
--- a/editors/vscode/client/vmproc.js
+++ b/editors/vscode/client/vmproc.js
@@ -16,6 +16,7 @@ function vmProcess(dir, opts = {}) {
     const log = opts.log || (() => {});
     const { TinyVM } = require(path.join(dir, 'tinyvm.js'));
     const image = require(path.join(dir, 'lsp.json'));
+    const words = require('fs').readFileSync(path.join(dir, 'lsp.bin'));
     const proc = new EventEmitter();
     const out = new EventEmitter();
     const err = new EventEmitter();
@@ -33,8 +34,8 @@ function vmProcess(dir, opts = {}) {
             err.emit('data', Buffer.from(m, 'utf8'));
         },
     });
-    vm.loadGenome(image.words, image.gorg);
-    log('message', 'loaded the image: ' + image.words.length + ' words, code at ' + image.gorg);
+    const loaded = vm.loadImage(words, image.gorg);
+    log('message', 'loaded the image: ' + loaded + ' words, code at ' + image.gorg);
 
     const flush = () => {
         if (pending.length) {
diff --git a/examples/quine.zc b/examples/quine.zc
index 58a5351..3fb563b 100644
--- a/examples/quine.zc
+++ b/examples/quine.zc
@@ -1,4 +1 @@
-namespace;
-include rt;
-
-let s="let s=#;void main(){let i=0;while(s[i]){if(s[i]==35){put_c(34);put_s(s);put_c(34);}else put_c(s[i]);i++;}put_c(10);return;}";void main(){let i=0;while(s[i]){if(s[i]==35){rt.put_c(34);rt.put_s(s);rt.put_c(34);}else rt.put_c(s[i]);i++;}rt.put_c(10);return;}
+namespace;include rt;let s="namespace;include rt;let s=#;void main(){let i=0;while(s[i]){if(s[i]==35){rt.put_c(34);rt.put_s(s);rt.put_c(34);}else rt.put_c(s[i]);i++;}rt.put_c(10);return;}";void main(){let i=0;while(s[i]){if(s[i]==35){rt.put_c(34);rt.put_s(s);rt.put_c(34);}else rt.put_c(s[i]);i++;}rt.put_c(10);return;}
diff --git a/src/baremetal/run.sh b/src/baremetal/run.sh
index 467e86e..43f8a4c 100755
--- a/src/baremetal/run.sh
+++ b/src/baremetal/run.sh
@@ -6,11 +6,12 @@
 #   src/baremetal/run.sh riscv|aarch64 compile examples/hello.zc
 # run:    the program is compiled into the image. nothing is read.
 # io:     the same image, but stdin is the program's input and 0x04 ends it.
-# compile: the default 1,048,576-word genome. the source, a backtick, and
+# compile: the default compiler genome (build/core/genome.bin, from make genome). the source, a backtick, and
 #          0x04 are written to the UART. the backtick ends the unit; the
 #          0x04 is what eof() waits for after that.
 # Prints the program's UART output and nothing else. Exits 0 on a clean
-# power-off. A missing toolchain exits 0 from `ready` and 1 otherwise.
+# power-off. A missing toolchain exits 0 from `ready` and 1 otherwise. the cross
+# compilers need c23 #embed (gcc 15 or later) to take in the genome.
 set -euo pipefail
 case "${1:-}" in
     --help|-h) printf '%s\n' 'usage: src/baremetal/run.sh ready riscv|aarch64' '       src/baremetal/run.sh riscv|aarch64 run|io|compile FILE.zc' 'builds a freestanding microcore and boots it in qemu-system.' 'run compiles the program into the image; io also forwards program input.' 'compile sends source to the resident compiler over the uart.' 'ready checks for the cross compiler and emulator.'; exit 0 ;;
@@ -66,9 +67,9 @@ common="$cflags -ffreestanding -fno-pic -fno-pie -fno-builtin -fno-unwind-tables
 
 if [ "$mode" = run ] || [ "$mode" = io ]; then
 	# the map is sized to the program, so a bigger runtime or program just gets a bigger board
-	gcc -O2 -w src/tools/genmap.c -o "$D/genmap"
+	${CC:-$(sh src/tools/findcc.sh)} -O2 -w src/tools/genmap.c -o "$D/genmap"
 	GENMAP="$D/genmap" bash src/tools/automap.sh run "$D/img" src/runtime/run.zc "$src" >"$D/genmap.log" 2>&1 || { cat "$D/genmap.log" >&2; exit 1; }
-	cp src/micro/micro.c src/micro/micro_port.h src/core/fops.h src/core/bops.h src/core/stack.h "$D/img/"
+	cp src/micro/micro.c src/micro/micro_port.h src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h "$D/img/"
 	"$cc" $common $def -I"$D/img" -c "$D/img/micro.c" -o "$D/micro.o"
 	if [ "$mode" = io ]; then
 		"$cc" $common $def -DBARE_INPUT=1 -I"$D/img" -c src/baremetal/port.c -o "$D/port.o"
@@ -78,7 +79,8 @@ if [ "$mode" = run ] || [ "$mode" = io ]; then
 		timeout=120
 	fi
 elif [ "$mode" = compile ]; then
-	cp src/micro/micro.c src/micro/micro_port.h src/core/memmap.h build/core/genome.h src/core/fops.h src/core/bops.h src/core/stack.h "$D/"
+	[ -f build/core/genome.bin ] || { echo "baremetal: no build/core/genome.bin; run make genome first" >&2; exit 1; }
+	cp src/micro/micro.c src/micro/micro_port.h build/core/map/memmap.h build/core/genome.bin src/core/genome.h src/core/fops.h src/core/bops.h src/core/stack.h "$D/"
 	"$cc" $common $def -I"$D" -c "$D/micro.c" -o "$D/micro.o"
 	"$cc" $common $def -DBARE_INPUT=1 -I"$D" -c src/baremetal/port.c -o "$D/port.o"
 	timeout=90
diff --git a/src/compiler/compiler.zc b/src/compiler/compiler.zc
index c33005d..244efc5 100644
--- a/src/compiler/compiler.zc
+++ b/src/compiler/compiler.zc
@@ -256,6 +256,7 @@ int s_star, s_slash, s_amp, s_colon, s_hash, s_minus, s_andand, s_oror;
 int s_dot, s_fn, s_var, s_const, s_else, s_as, s_unchecked, s_immediate, s_m, s_d, s_u;
 int s_q, s_case, s_default, s_fovf, s_start, s_main, s_free, s_recycle, s_own, s_qnew, s_enhance, s_micro, s_vm;
 int s_frame_floor, s_frame_top, s_frame_node, s_frame_busy, s_frame_guard, s_frame_grow, s_frame_leave;
+int s_copy_w;
 int s_do, s_while, s_enum, s_include, s_memdebug, s_scrub, s_alloc, s_check, s_memset, s_static;
 
 //: ---- types: kinds, tables and parser state (see the types section) ----
@@ -1067,6 +1068,21 @@ int module_imported(char* name) {
 	while (p) { if (rt.eq_w(p[1], name)) return 1; p = p[0]; }
 	return 0;
 }
+// modules reported missing in this unit, so their names are not reported again as undefined
+word missing_imports;
+// true when name is qualified by a module this unit was already told to include.
+int missing_import_name(char* name) {
+	int i = 0; word p = missing_imports;
+	while (name[i] && name[i] != '.') i++;
+	if (!name[i]) return 0;
+	while (p) {
+		char* module = p[1]; int k = 0;
+		while (k < i && module[k] == name[k]) k++;
+		if (k == i && !module[k]) return 1;
+		p = p[0];
+	}
+	return 0;
+}
 // source references require their module's explicit import; compiler-generated calls use lookup directly.
 int source_lookup(char* name) {
 	int i = 0, s; char* owner;
@@ -1074,7 +1090,9 @@ int source_lookup(char* name) {
 	if (name[i]) {
 		owner = chk_resize(0, 0, i + 1); rt.copy_w(owner, name, i); owner[i] = 0;
 		if ((module_known(owner) || module_loaded(owner)) && !module_imported(owner)) {
-			errat(); rt.put_s("module access requires `include "); rt.put_s(owner); rt.put_s(";`"); errend(); return -1;
+			errat(); rt.put_s("module access requires `include "); rt.put_s(owner); rt.put_s(";`"); errend();
+			word link = chk_resize(0, 0, 2); link[0] = missing_imports; link[1] = owner; missing_imports = link;
+			// the unit already fails; resolving the name anyway keeps later diagnostics about the real code
 		}
 	}
 	if (module_name) { s = lookup_raw(module_symbol(name)); if (s >= 0) return s; }
@@ -4532,37 +4550,22 @@ int cover_warn(int e, int cov, int sl) {
 	return 0;
 }
 //: ---- include ----
-//: the text of the embedded std library, one character to a word and ending in 0, as readfile gives a file.
-//: it is built from the pieces src/tools/embed.sh put at the end of this file, the first time it is asked for
+//: the text of an embedded library, one character to a word and ending in 0, as readfile gives a file.
+//: it is unpacked from the byte string the first time it is asked for.
+char* bstr_text(bstr p) {
+	int n = rt.len_s(p), i = 0; char* b = m*rt.new(n + 2);
+	while (i < n) { b[i] = rt.at_s(p, i); i++; }
+	b[n] = 0;
+	return b;
+}
+// the embedded std module.
 char* std_text() {
-	int n = 0, i = 0, k = 0, j; bstr p; char* b;
-	if (std_buf) return std_buf;
-	while (1) { p = std_part(i); if (!p) break; n = n + rt.len_s(p); i++; }
-	b = rt.new(n + 2);
-	i = 0;
-	while (1) {
-		p = std_part(i); if (!p) break;
-		j = 0; while (j < rt.len_s(p)) { b[k] = rt.at_s(p, j); k++; j++; }
-		i++;
-	}
-	b[k] = 0;
-	std_buf = b;
+	if (!std_buf) std_buf = bstr_text(std_source());
 	return std_buf;
 }
-// the embedded icon module, assembled from its source pieces on first use.
+// the embedded icon module.
 char* icon_text() {
-	int n = 0, i = 0, k = 0, j; bstr p; char* b;
-	if (icon_buf) return icon_buf;
-	while (1) { p = icon_part(i); if (!p) break; n = n + rt.len_s(p); i++; }
-	b = rt.new(n + 2);
-	i = 0;
-	while (1) {
-		p = icon_part(i); if (!p) break;
-		j = 0; while (j < rt.len_s(p)) { b[k] = rt.at_s(p, j); k++; j++; }
-		i++;
-	}
-	b[k] = 0;
-	icon_buf = b;
+	if (!icon_buf) icon_buf = bstr_text(icon_source());
 	return icon_buf;
 }
 // a path with its . and .. segments and doubled slashes taken out: /a/b/../c/./d.zc is /a/c/d.zc
@@ -4714,6 +4717,120 @@ int kw_include() {
 	inc_compile(buf, incres, inc_dir(incres));
 	return 0;
 }
+// embed "path" as [type] name;  declares name with the bytes of the file at path, read
+// when the unit is compiled. the path is found the way an include's is. with no type, or
+// bstr, name is a byte string of the file; char* gives one character to a word; a number
+// type takes the bytes little-endian (a float or f32 needs exactly its size); T[] and
+// T[n] lay the bytes out as the array's elements, packed for the sized types, one byte
+// to an element for char[]. at the top level name is a global, in a function a local.
+int kw_embed() {
+	int pp, off, n, t = 0, i, w, count, k, a, j, v, sz, skip = -1; char* path; word data;
+	stmtonly();
+	next();
+	pp = tpack();
+	if (tk != T_STR) { die("embed takes a path in quotes: embed \"file\" as name;"); return 0; }
+	path = tv; next();
+	if (!is_id(s_as)) { die("expected as: embed \"file\" as [type] name;"); return 0; }
+	next();
+	peekat(0);
+	if (!(tk == T_ID && pk_tk == T_OP && pk_tv == s_semi)) t = ptype();
+	off = toff; n = name();
+	expect(s_semi);
+	data = m*embed_open(path);
+	if (!data) { int sv = tpack(); tunpack(pp); serr("can't read the file named by embed"); tunpack(sv); data = chk_resize(0, 0, 1); }
+	sz = data[0];
+	if (!t) t = tbstr;
+	// in a function the data sits in the code stream, so the code jumps over it
+	if (infn && (t == tbstr || t == tptr(tchar) || t[0] == TY_ARR)) { reserve_code(2); skip = hole(); op(O_JMP); }
+	if (t == tbstr || t == tptr(tchar)) {
+		if (t == tbstr) { a = embed_bstr(data); }
+		else { reserve_code(sz + 1); a = here; i = 0; while (i < sz) { emit(data[1 + i]); i++; } emit(0); }
+		if (skip >= 0) setlit(skip, here);
+		return embed_bind(n, off, t, a, 0);
+	}
+	if (t[0] == TY_ARR) {
+		w = embed_width(t[4]);
+		if (!w) { serr("embed declares a bstr, a char*, a number, or an array of numbers"); if (skip >= 0) setlit(skip, here); return 0; }
+		if (sz % w) { serr("the embedded file's size is not a whole number of array elements"); if (skip >= 0) setlit(skip, here); return 0; }
+		count = sz / w;
+		if (t[3] >= 0 && count > t[3]) { serr("the embedded file is larger than the array it is declared as"); if (skip >= 0) setlit(skip, here); return 0; }
+		if (t[3] < 0) t = tarr(t[4], count);
+		k = tsz(t); reserve_code(k); a = here; i = 0;
+		if (t[4][0] == TY_CHAR) { while (i < k) { if (i < sz) emit(data[1 + i]); else emit(0); i++; } }
+		else {
+			while (i < k) {
+				v = 0; j = 0;
+				while (j < 8) { if (i * 8 + j < sz) v = v | (data[1 + i * 8 + j] << (j * 8)); j++; }
+				emit(v); i++;
+			}
+		}
+		if (skip >= 0) setlit(skip, here);
+		return embed_bind(n, off, t, a, 1);
+	}
+	w = embed_width(t);
+	if (!w) { serr("embed declares a bstr, a char*, a number, or an array of numbers"); return 0; }
+	if (sz > w) { serr("the embedded file is larger than the type it is declared as"); return 0; }
+	if (isfl(t) && sz != w) { serr("an embedded float takes exactly as many bytes as its type"); return 0; }
+	v = 0; i = 0;
+	while (i < sz) { v = v | (data[1 + i] << (i * 8)); i++; }
+	if (isfl(t) && w == 4) v = rt.s2f(v);
+	else v = cnorm(t, v);
+	return embed_bind(n, off, t, v, 2);
+}
+// the bytes one element of type t takes in an embedded file: the packed size of a
+// sized type or f32, 1 for char, 8 for the other number types, 0 when t is not a number.
+int embed_width(word t) {
+	if (tbytes(t)) return tbytes(t);
+	if (t[0] == TY_CHAR) return 1;
+	if (t[0] == TY_INT || t[0] == TY_WORD || t[0] == TY_BOOL || t[0] == TY_FLOAT) return 8;
+	return 0;
+}
+// the bytes of block data ([n, b0, b1, ...]) as byte string storage in the code stream.
+int embed_bstr(word data) {
+	int n = data[0], a, i = 0, w, k;
+	reserve_code((n >> 3) + 2); a = here;
+	emit(n);
+	while (i < n) {
+		w = 0; k = 0;
+		while (k < 8 && i < n) { w = w | (data[1 + i] << (k * 8)); k++; i++; }
+		emit(w);
+	}
+	if (!(n & 7)) emit(0);
+	return a;
+}
+// declare name of type t. kind 0: a is the address of the data, which becomes the value;
+// kind 1: a is an array's storage; kind 2: a is the value itself. a global keeps the
+// value in its slot; a local is initialized from it, and a local array copies the storage.
+int embed_bind(int n, int off, word t, int a, int kind) {
+	int s, i;
+	if (!infn) {
+		if (kind == 1) { s = addsym(n, K_GARR, a); }
+		else { reserve_code(1); s = addsym(n, K_GVAR, here); emit(a); }
+		rs_put(off, RS_SYM, rs_sym(s), s); stype[s] = t;
+		lt_note(off, t);
+		return 0;
+	}
+	i = newloc(n); lrsoff[i] = off; rs_note(RS_LOCAL, off);
+	ltag[i] = LDECL; lpos[i] = tpack(); lnsz[i] = 0; lleaf[i] = 0; ltype[i] = t;
+	if (kind == 1) {
+		larr[i] = 1; fslots = fslots + tsz(t); capture_cell(i, 0);
+		vaddr(i); lit(a); lit(tsz(t)); callname(s_copy_w); op(O_DROP);
+	} else {
+		fslots++; if (isfl(t)) setflt(i, 1); capture_cell(i, 0);
+		lit(a); vaddr(i); op(O_ST);
+		setstr(i, t == tbstr);
+	}
+	lt_note(off, t);
+	return 0;
+}
+// the bytes of an embedded file as [n, b0, b1, ...], found next to the including file,
+// then in the workspace folder, then as written, like an include. 0 when none opens.
+word.u embed_open(char*.m path) {
+	if (path[0] != '/' && incdir) { char* combined = inc_cat(incdir, path); char* c = inc_norm(combined); word b = rt.readbytes(c); if (b) return b; }
+	if (path[0] != '/' && increoot) { char* combined = inc_cat(increoot, path); char* c = inc_norm(combined); word b = rt.readbytes(c); if (b) return b; }
+	word b = rt.readbytes(path);
+	return b;
+}
 // file namespace and imports are restored when an included source ends.
 int kw_namespace() {
 	next();
@@ -9201,8 +9318,9 @@ int fn_remember(int s, int name) {
 	}
 	if (depth) return 0;
 	close = j;
-	q = rt.new(1 + count * 3); q[0] = count; rt.copy_w(q + 1, gbuf + 1, count * 3);
-	meta = rt.new(6); meta[0] = q; meta[1] = module_name; meta[2] = module_imports;
+	// compiler storage, not program objects: internal, so live_objects and leak reports skip it
+	q = chk_resize(0, 0, 1 + count * 3); q[0] = count; rt.copy_w(q + 1, gbuf + 1, count * 3);
+	meta = chk_resize(0, 0, 6); meta[0] = q; meta[1] = module_name; meta[2] = module_imports;
 	meta[3] = namepos; meta[4] = open; meta[5] = close; fnmeta[s] = meta;
 	return 1;
 }
@@ -9407,7 +9525,7 @@ int unit_end(int from) {
 	while (i < nsym) {
 		// a bodyless declaration (fn f();) promises a definition elsewhere. in check mode that
 		// elsewhere is another file of the same build, which this document can't see
-		if (skind[i] == K_FN && !(sflag[i] & F_DEF) && sfix[i] && !(cmode && (sflag[i] & F_DECL))) {
+		if (skind[i] == K_FN && !(sflag[i] & F_DEF) && sfix[i] && !(cmode && (sflag[i] & F_DECL)) && !missing_import_name(sname[i])) {
 			tunpack(sval[i]);
 			best = similar(sname[i]);
 			if (!dry) {
@@ -9419,6 +9537,7 @@ int unit_end(int from) {
 		}
 		i++;
 	}
+	missing_imports = 0;
 	if (nerr) giveup();
 	return 0;
 }
@@ -9657,7 +9776,7 @@ int zc_init() {
 	s_start = intern("run.start");
 	s_main = intern("main");
 	s_free = intern("rt.free");
-	s_recycle = intern("rt.recycle");
+	s_recycle = intern("rt.recycle"); s_copy_w = intern("rt.copy_w");
 	s_do = intern("do");
 	s_while = intern("while");
 	s_enum = intern("enum");
@@ -9706,6 +9825,7 @@ int zc_tables() {
 	add_kw("do", kw_do, F_STMT);
 	add_kw("enum", kw_enum, F_STMT | F_TOP);
 	add_kw("include", kw_include, F_TOP | F_STMT);
+	add_kw("embed", kw_embed, F_TOP | F_STMT);
 	add_kw("run.method", kw_method, F_TOP | F_STMT);
 	add_kw("run.share_value", kw_share_value, F_EXPR);
  add_kw("run.syntax", kw_syntax, F_TOP | F_STMT);
@@ -9903,31 +10023,9 @@ int hl_end() {
 	pq_n = 0;
 	return 0;
 }
-// ---- embedded std library (generated by src/tools/embed.sh from src/lib/std.zc; do not edit) ----
-bstr std_part(int i) {
-	if (i == 0) return b"namespace std;\ninclude rt, run;\n\n// small helpers for strings, files, the clock and byte buffers. not part of the\n// genome as declarations; its source is embedded. include it with: include std;\n// syscall numbers (SYS_OPEN and the rest) live in the runtime.\n// a character string has type char*, one character per word and a 0 at the end.\n// the Bytes group takes packed byte strings (b\"...\"), whose\n// type is bstr.\n// the helpers are grouped in structs, and each is a static function, so it is\n// called as std.Group.name(args): std.Text.itoa(n, buf), std.Host.now(),\n// std.Buf.get(b, 0).\n// the constructors arena(n) and bnew(n) and the argv helpers are plain\n// functions, because an owned result has to carry its .u tag.\n\n//: ---- the command line and the environment ----\n\n//: argc and argv, envc and envp, as passed to main by c. a zc string is\n//: one character per word, so an array of them is char*[?]. libinit() fills\n//: these and the runtime calls it before main, if the program has one (an\n//: image built by build_image, or a check-mode document, does not).\n\nint argc;\nchar*[?] argv;\nint envc;\nchar*[?] envp;\n\n// one entry of a vector syscall, as a fresh string, or 0 past the end.\n//   op: the syscall that fetches an entry (SYS_ARG or SYS_ENV)\n//   i: which entry\n//   returns: the entry, owned by the caller; 0 when there is no entry i\nchar*.u argstr(int op, int i) {\n\tint n = rt.syscall(op, i, 0, 0);\n\tchar* s;\n\tif (n < 0) return 0;\n\ts = rt.new(n + 1);\n\trt.syscall(op, i, s, n + 1);\n\treturn s;\n}\n\n// every entry of a vector syscall, in order.\n//   cntop: the syscall that counts the entries (SYS_ARGC or SYS_ENVC)\n//   stop: the syscall that fetches one (SYS_ARG or SYS_ENV)\n//   returns: a new array of the strings, owned by the caller\nchar*[?].u argsvec(int cntop, int stop) {\n\tint n = rt.syscall(cntop, 0, 0, 0), i = 0;\n\tchar*[?] a = rt.new(char*[?], 0);\n\twhile (i < n) { push(a, argstr(stop, i)); i++; }\n\treturn a;\n}\n\n// reads the command line and the environment into argc, argv, envc and envp.\n// it stays a plain function: the compiler looks it up by name.\n//   returns: 0\nint libinit() {\n\targv = argsvec(rt.SYS_ARGC, rt.SYS_ARG);\n\tenvp = argsvec(rt.SYS_ENVC, rt.SYS_ENV);\n\targc = len(argv); envc = len(envp);\n\treturn 0;\n}\n\n//: ---- capturing output ----\n\n// capture.start() redirects everything the program writes into a string and\n// returns it. writes go to the buffer instead of the terminal until end()\n// stops it, so the buffer is a string once end() has run:\n//   let buf = capture.start();\n//   put_s(\"hello world!\");   // nothing on the terminal\n//   capture.end(buf);\n//   put_s(buf);              // hello world\n// one capture at a time, and the buffer belongs to whoever holds it.\n\nstruct capture {\n\t// redirects program output into a collector-managed character buffer.\n\t// returns the buffer; call end(buffer) before reading its terminator.\n\t//   returns: the buffer used for this capture\n\tstatic char* start() {\n\t\tint cap = 256;\n\t\trt.outmode = 2; rt.outn =";
-	if (i == 1) return b" 0; rt.outcap = cap;\n\t\trt.outbuf = rt.new(cap);\n\t\treturn rt.outbuf;\n\t}\n\t// stops output capture, terminates the buffer, and returns the collected text.\n\t//   buffer: the buffer returned by start\n\t//   returns: the same buffer, now terminated\n\tstatic char* end(char* buffer) {\n\t\trt.outbuf[rt.outn] = 0;\n\t\trt.outmode = 0; rt.outbuf = 0; rt.outn = 0; rt.outcap = 0;\n\t\treturn buffer;\n\t}\n}\n\n//: ---- character strings ----\n\nstruct Text {\n\t// the number written in decimal at the start of s. a leading '-' makes it\n\t// negative and the first character that is not a digit ends it.\n\t//   s: the string to read\n\t//   returns: the number, 0 when s starts with no digit\n\tstatic int atoi(char* s) {\n\t\tint n = 0, i = 0, sign = 1;\n\t\tif (s[0] == '-') { sign = 0 - 1; i = 1; }\n\t\twhile (s[i] >= '0' && s[i] <= '9') { n = n * 10 + s[i] - '0'; i++; }\n\t\treturn n * sign;\n\t}\n\n\t// writes n in decimal into dst, with a 0 after it.\n\t//   n: the number\n\t//   dst: where the text goes; 24 words is always enough\n\t//   returns: how many characters were written, not counting the 0\n\tstatic int itoa(int n, char* dst) {\n\t\tint b[24], i = 0, j = 0, neg = 0;\n\t\tif (!n) { dst[0] = '0'; dst[1] = 0; return 1; }\n\t\tif (n < 0) { neg = 1; n = 0 - n; }\n\t\tif (n < 0) { rt.copy_w(dst, \"-9223372036854775808\", 21); return 20; }\n\t\twhile (n) { b[i] = '0' + n % 10; i++; n = n / 10; }\n\t\tif (neg) { dst[0] = '-'; j = 1; }\n\t\twhile (i) { i--; dst[j] = b[i]; j++; }\n\t\tdst[j] = 0;\n\t\treturn j;\n\t}\n\n\t// joins two strings.\n\t//   dst: where the result goes, with room for both and a 0; not a or b\n\t//   a: the first string\n\t//   b: the second string\n\t//   returns: the length of the result\n\tstatic int cat(char* dst, char* a, char* b) {\n\t\tint i = 0, j = 0;\n\t\twhile (a[i]) { dst[j] = a[i]; i++; j++; }\n\t\ti = 0;\n\t\twhile (b[i]) { dst[j] = b[i]; i++; j++; }\n\t\tdst[j] = 0;\n\t\treturn j;\n\t}\n\n\t// does s begin with pfx?\n\t//   s: the string to test\n\t//   pfx: the beginning to look for\n\t//   returns: 1 if it does (always, for an empty pfx), 0 if not\n\tstatic int starts(char* s, char* pfx) {\n\t\tint i = 0;\n\t\twhile (pfx[i]) { if (s[i] != pfx[i]) return 0; i++; }\n\t\treturn 1;\n\t}\n\n\t// does s end with suffix? an empty suffix always matches.\n\t//   s: the string to test\n\t//   suffix: the ending to look for\n\t//   returns: 1 when it matches, 0 otherwise\n\tstatic int ends(char* s, char* suffix) {\n\t\tint n = 0, m = 0, i = 0;\n\t\twhile (s[n]) n++;\n\t\twhile (suffix[m]) m++;\n\t\tif (m > n) return 0;\n\t\twhile (i < m) { if (s[n - m + i] != suffix[i]) return 0; i++; }\n\t\treturn 1;\n\t}\n\n\t// how many characters come before the 0.\n\t//   s: the string\n\t//   returns: the length, not counting the 0\n\tstatic int len(char* s) {\n\t\tint n = 0;\n\t\twhile (s[n]) n++;\n\t\treturn n;\n\t}\n\n\t// are the two strings the same, character for character?\n\t//   a, b: the strings to compare\n\t//   returns: 1 if they are equal, 0 if not\n\tstatic int eq(char* a, char* b) {\n\t\tint i = 0;\n\t\twhile (a[i] && a[i] == b[i]) i++;\n\t\treturn a[i] == b[i];\n\t}\n\n\t// copies s into dst, with a 0 after it.\n\t//   dst: where th";
-	if (i == 2) return b"e copy goes, with room for s and the 0\n\t//   s: the string to copy\n\t//   returns: the length of the copy\n\tstatic int copy(char* dst, char* s) {\n\t\tint i = 0;\n\t\twhile (s[i]) { dst[i] = s[i]; i++; }\n\t\tdst[i] = 0;\n\t\treturn i;\n\t}\n\n\t// where pat first appears in s.\n\t//   s: the string to search\n\t//   pat: the string to look for; an empty pat is found at 0\n\t//   returns: the index of the first match, or -1 when there is none\n\tstatic int find(char* s, char* pat) {\n\t\tint i = 0, j;\n\t\tif (!pat[0]) return 0;\n\t\twhile (s[i]) {\n\t\t\tj = 0;\n\t\t\twhile (pat[j] && s[i + j] == pat[j]) j++;\n\t\t\tif (!pat[j]) return i;\n\t\t\ti++;\n\t\t}\n\t\treturn 0 - 1;\n\t}\n\n\t// changes the ASCII letters of s to lower case, in place.\n\t//   s: the string to change\n\t//   returns: the length of s\n\tstatic int lower(char* s) {\n\t\tint i = 0;\n\t\twhile (s[i]) {\n\t\t\tif (s[i] >= 'A' && s[i] <= 'Z') s[i] = s[i] + 32;\n\t\t\ti++;\n\t\t}\n\t\treturn i;\n\t}\n\n\t// changes the ASCII letters of s to upper case, in place.\n\t//   s: the string to change\n\t//   returns: the length of s\n\tstatic int upper(char* s) {\n\t\tint i = 0;\n\t\twhile (s[i]) {\n\t\t\tif (s[i] >= 'a' && s[i] <= 'z') s[i] = s[i] - 32;\n\t\t\ti++;\n\t\t}\n\t\treturn i;\n\t}\n\n\t// removes the spaces, tabs and line breaks from both ends of s, in place.\n\t//   s: the string to change\n\t//   returns: the length of what is left\n\tstatic int trim(char* s) {\n\t\tint n = 0, a = 0, b, i = 0, c;\n\t\twhile (s[n]) n++;\n\t\twhile (a < n && (s[a] == ' ' || s[a] == '\\t' || s[a] == '\\n' || s[a] == '\\r')) a++;\n\t\tb = n;\n\t\twhile (b > a) {\n\t\t\tc = s[b - 1];\n\t\t\tif (!(c == ' ' || c == '\\t' || c == '\\n' || c == '\\r')) break;\n\t\t\tb--;\n\t\t}\n\t\tn = b - a;\n\t\twhile (i < n) { s[i] = s[i + a]; i++; }\n\t\ts[n] = 0;\n\t\treturn n;\n\t}\n}\n\n//: ---- numbers ----\n\n// plain integer helpers. none of them can fail: an out of range result wraps\n// the same way the arithmetic does.\n\nstruct Num {\n\t// the absolute value of n, using wrapping word arithmetic. the minimum\n\t// word remains negative because its positive value cannot fit in a word.\n\t//   n: the value\n\t//   returns: its absolute value, or the minimum word\n\tstatic int abs(int n) {\n\t\tif (n < 0) return 0 - n;\n\t\treturn n;\n\t}\n\n\t// the smaller of a and b.\n\t//   a, b: the values to compare\n\t//   returns: the smaller value (a when they are equal)\n\tstatic int min(int a, int b) {\n\t\tif (a < b) return a;\n\t\treturn b;\n\t}\n\n\t// the larger of a and b.\n\t//   a, b: the values to compare\n\t//   returns: the larger value (a when they are equal)\n\tstatic int max(int a, int b) {\n\t\tif (a > b) return a;\n\t\treturn b;\n\t}\n\n\t// v, kept between lo and hi.\n\t//   v: the value\n\t//   lo, hi: the bounds, lo first; lo must not exceed hi\n\t//   returns: v clamped to the bounds\n\tstatic int clamp(int v, int lo, int hi) {\n\t\tif (v < lo) return lo;\n\t\tif (v > hi) return hi;\n\t\treturn v;\n\t}\n\n\t// the greatest common divisor of a and b, computed with word arithmetic.\n\t//   a, b: the values\n\t//   returns: their greatest common divisor\n\tstatic int gcd(int a, int b) {\n\t\tif (a < 0) a = 0 - a;\n\t\tif (b < 0) b = 0 - b;\n\t\tint t;\n\t\twhile (b) { t ";
-	if (i == 3) return b"= a % b; a = b; b = t; }\n\t\treturn a;\n\t}\n\n\t// b raised to the power e. e below 0 gives 1; the result wraps as a word.\n\t//   b: the base\n\t//   e: the exponent\n\t//   returns: b to the power e, or 1 when e is negative\n\tstatic int pow(int b, int e) {\n\t\tint r = 1;\n\t\twhile (e > 0) { r = r * b; e--; }\n\t\treturn r;\n\t}\n\n\t// the whole square root of n, rounded down. n below 0 gives 0.\n\t//   n: the value\n\t//   returns: the greatest integer whose square is at most n, or 0 for n <= 0\n\tstatic int isqrt(int n) {\n\t\tint lo = 0, hi = 3037000499, mid;\n\t\tif (n <= 0) return 0;\n\t\twhile (lo < hi) {\n\t\t\tmid = lo + (hi - lo + 1) / 2;\n\t\t\tif (mid <= n / mid) lo = mid; else hi = mid - 1;\n\t\t}\n\t\treturn lo;\n\t}\n\n\t// -1, 0 or 1 according to the sign of n.\n\t//   n: the value\n\t//   returns: -1 when n is negative, 0 when it is zero, and 1 when it is positive\n\tstatic int sign(int n) {\n\t\tif (n < 0) return 0 - 1;\n\t\tif (n > 0) return 1;\n\t\treturn 0;\n\t}\n}\n\n//: ---- the host ----\n\n//: the argument block for Host.raw: the number, then its six arguments.\nint rawblk[7];\n\nstruct Host {\n\t// calls any linux system call on the host. this is the escape hatch below\n\t// the named helpers: the number is the kernel's, so the meaning of each\n\t// argument depends on the call. a pointer argument is an address in the\n\t// program's memory, and only the host reads it, so a string or buffer has\n\t// to be passed as its address.\n\t// it runs the call on the real machine, not inside the vm, so a program\n\t// that uses it can do whatever the process can do. only use it where that\n\t// is wanted.\n\t//   nr: the syscall number (x86-64 and arm64 numbers differ, so check the host)\n\t//   a..f: the six arguments, unused ones 0\n\t//   returns: the kernel's result, -errno on failure, or -1 on unsupported hosts\n\tstatic int raw(int nr, int a, int b, int c, int d, int e, int f) {\n\t\trawblk[0] = nr; rawblk[1] = a; rawblk[2] = b; rawblk[3] = c;\n\t\trawblk[4] = d; rawblk[5] = e; rawblk[6] = f;\n\t\treturn rt.syscall(rt.SYS_RAW, rawblk, 0, 0);\n\t}\n\n\t// the value of an environment variable.\n\t//   name: the variable's name\n\t//   dst: where the value goes, a zero-terminated character string\n\t//   n: how many words dst has\n\t//   returns: the length of the value, -1 if the variable is not set\n\tstatic int env(char* name, char* dst, int n) { return rt.syscall(rt.SYS_GETENV, name, dst, n); }\n\n\t// the clock.\n\t//   returns: the time in seconds since 1970\n\tstatic int now() { return rt.syscall(rt.SYS_TIME, 0, 0, 0); }\n\n\t// writes a string to a file, replacing what was there.\n\t//   path: the file's name\n\t//   s: the text to write\n\t//   returns: how many bytes were written, -1 if the file could not be opened\n\tstatic int writefile(char* path, char* s) {\n\t\tint fd = rt.syscall(rt.SYS_OPEN, path, 1, 0), n;\n\t\tif (fd < 0) return -1;\n\t\tn = rt.syscall(rt.SYS_WRITE, fd, s, rt.len_w(s));\n\t\trt.syscall(rt.SYS_CLOSE, fd, 0, 0);\n\t\treturn n;\n\t}\n}\n\n//: ---- byte strings ----\n\n// the same helpers for packed byte strings. character-string helpers above are unchanged.\n// a";
-	if (i == 4) return b" packed byte string has type bstr; len_s reads its stored byte length.\n\nstruct Bytes {\n\t// reads a decimal number at the start of s; a leading '-' makes it\n\t// negative, and the first non-digit ends the number.\n\t//   s: the byte string\n\t//   returns: the number, or 0 when s starts with no digit\n\tstatic int atoi(bstr s) { return rt.s_to_n(s); }\n\n\t// like Text.itoa, but the text is made fresh.\n\t//   n: the number\n\t//   returns: a new byte string\n\tstatic bstr itoa(int n) { return rt.n_to_s(n); }\n\n\t// like Text.starts, for byte strings.\n\t//   s: the byte string to test\n\t//   pfx: the beginning to look for\n\t//   returns: 1 if s begins with pfx, 0 if not\n\tstatic int starts(bstr s, bstr pfx) {\n\t\tint i = 0, n = rt.len_s(s), m = rt.len_s(pfx);\n\t\tif (m > n) return 0;\n\t\twhile (i < m) { if (rt.at_s(s, i) != rt.at_s(pfx, i)) return 0; i++; }\n\t\treturn 1;\n\t}\n\n\t// the number of bytes in a packed byte string.\n\t//   s: the byte string\n\t//   returns: its stored length\n\tstatic int len(bstr s) { return rt.len_s(s); }\n\n\t// are two packed byte strings equal, byte for byte.\n\t//   a, b: the byte strings to compare\n\t//   returns: 1 if equal, 0 otherwise\n\tstatic int eq(bstr a, bstr b) {\n\t\tint i = 0;\n\t\tif (rt.len_s(a) != rt.len_s(b)) return 0;\n\t\twhile (i < rt.len_s(a)) { if (rt.at_s(a, i) != rt.at_s(b, i)) return 0; i++; }\n\t\treturn 1;\n\t}\n\n\t// where pat first appears in s.\n\t//   s: the byte string to search\n\t//   pat: the byte string to find; an empty pat is found at 0\n\t//   returns: its byte index, or -1 when absent\n\tstatic int find(bstr s, bstr pat) {\n\t\tint i = 0, j, n = rt.len_s(s), m = rt.len_s(pat);\n\t\tif (!m) return 0;\n\t\twhile (i + m <= n) {\n\t\t\tj = 0;\n\t\t\twhile (j < m && rt.at_s(s, i + j) == rt.at_s(pat, j)) j++;\n\t\t\tif (j == m) return i;\n\t\t\ti++;\n\t\t}\n\t\treturn 0 - 1;\n\t}\n\n\t// does s end with suffix? an empty suffix always matches.\n\t//   s: the byte string to test\n\t//   suffix: the ending to look for\n\t//   returns: 1 when it matches, 0 otherwise\n\tstatic int ends(bstr s, bstr suffix) {\n\t\tint n = rt.len_s(s), m = rt.len_s(suffix), i = 0;\n\t\tif (m > n) return 0;\n\t\twhile (i < m) { if (rt.at_s(s, n - m + i) != rt.at_s(suffix, i)) return 0; i++; }\n\t\treturn 1;\n\t}\n\n\t// like Host.env, for byte strings.\n\t//   name: the variable's name, a byte string\n\t//   dst: the packed byte string whose payload receives the value\n\t//   n: the maximum number of bytes to write\n\t//   returns: the length of the value, -1 if the variable is not set\n\tstatic int env(bstr name, bstr dst, int n) { return rt.bgetenv(name, dst, n); }\n\n\t// like Host.writefile, for a byte string.\n\t//   path: the file's name, a byte string\n\t//   s: the bytes to write\n\t//   returns: how many bytes were written, -1 if the file could not be opened\n\tstatic int writefile(bstr path, bstr s) {\n\t\tint fd = rt.bopen(path, 1), n;\n\t\tif (fd < 0) return -1;\n\t\tn = rt.bwrite(fd, s, rt.len_s(s));\n\t\trt.syscall(rt.SYS_CLOSE, fd, 0, 0);\n\t\treturn n;\n\t}\n}\n\n//: ---- arenas ----\n\n// a region that is freed all at once.\n//   n: its capacity in words; value";
-	if (i == 5) return b"s below 1 allocate one word\n//   returns: the arena, owned by the caller\nint .u arena(int n) { return rt.arena_new(n); }\n\nstruct Arena {\n\t// takes n zeroed words from an arena.\n\t//   a: the arena\n\t//   n: how many words\n\t//   returns: the first word, or 0 when n words do not fit\n\tstatic int alloc(word a, int n) { return rt.arena_alloc(a, n); }\n\n\t// gives every block of an arena back at once. pointers returned by alloc\n\t// before the reset are no longer valid.\n\t//   a: the arena\n\t//   returns: 0\n\tstatic int reset(word a) { return rt.arena_reset(a); }\n}\n\n//: ---- growable byte buffers ----\n\n// a byte buffer stores its length and capacity in two words, followed by the\n// bytes, packed.\n//   n: the capacity in bytes; a negative value is treated as 0\n//   returns: an empty buffer with that capacity, owned by the caller\nword .u bnew(int n) {\n\tint words;\n\tword p;\n\tif (n < 0) n = 0;\n\twords = (n + 7) >> 3;\n\tp = rt.new(2 + words);\n\tp[0] = 0;\n\tp[1] = n;\n\treturn u*p;\n}\n\nstruct Buf {\n\t// how many bytes a buffer holds.\n\t//   b: the buffer\n\t//   returns: its length\n\tstatic int length(word b) { return b[0]; }\n\n\t// how many bytes a buffer can hold.\n\t//   b: the buffer\n\t//   returns: its capacity\n\tstatic int capacity(word b) { return b[1]; }\n\n\t// one byte of a buffer.\n\t//   b: the buffer\n\t//   i: the position\n\t//   returns: the byte, 0 when i is outside the buffer\n\tstatic int get(word b, int i) { if (i < 0 || i >= b[0]) return 0; return rt.ld8(rt.addr_b(b + 2) + i); }\n\n\t// sets one byte of a buffer. setting the byte at the current length makes the\n\t// buffer one longer.\n\t//   b: the buffer\n\t//   i: the position, below the capacity\n\t//   v: the value; only its low 8 bits are kept\n\t//   returns: the byte stored, 0 when i is outside the capacity\n\tstatic int set(word b, int i, int v) {\n\t\tif (i < 0 || i >= b[1]) return 0;\n\t\trt.st8(rt.addr_b(b + 2) + i, v & 255);\n\t\tif (i >= b[0]) b[0] = i + 1;\n\t\treturn v & 255;\n\t}\n}\n\n//: array algorithms borrow their input and visit elements in index order.\n//: map and filter return independent handles. reference elements are shared\n//: with the collector, so freeing the input does not invalidate the result.\n\n// the first index equal to value, or -1 when no element matches.\nint array_find<T>(fixed T[?].m source, T value) {\n\tint length = len(source);\n\tfor (int i = 0; i < length; i++) if (source[i] == value) return i;\n\treturn -1;\n}\n// true when an element equals value.\nint array_contains<T>(fixed T[?].m source, T value) { return array_find(source, value) >= 0; }\n// the first index whose predicate is true, or -1 when none matches.\nint array_find_if<T>(fixed T[?].m source, int(T).m predicate) {\n\tint length = len(source);\n\tfor (int i = 0; i < length; i++) if (predicate(source[i])) return i;\n\treturn -1;\n}\n// true when any element satisfies predicate; false for an empty array.\nint array_any<T>(fixed T[?].m source, int(T).m predicate) { return array_find_if(source, predicate) >= 0; }\n// true when every element satisfies predicate, including an ";
-	if (i == 6) return b"empty array.\nint array_all<T>(fixed T[?].m source, int(T).m predicate) {\n\tint length = len(source);\n\tfor (int i = 0; i < length; i++) if (!predicate(source[i])) return 0;\n\treturn 1;\n}\n// the number of elements satisfying predicate.\nint array_count<T>(fixed T[?].m source, int(T).m predicate) {\n\tint length = len(source);\n\tint count = 0;\n\tfor (int i = 0; i < length; i++) if (predicate(source[i])) count++;\n\treturn count;\n}\n// apply transform once to each element and return the transformed array.\n// the result element type follows the callback's return type.\nU[?].u array_map<T,U>(fixed T[?].m source, U(T).m transform) {\n\tint length = len(source);\n\tU[?] result = rt.new(U[?]);\n\tfor (int i = 0; i < length; i++) push(result, run.share_value(transform(source[i])));\n\treturn result;\n}\n// copy elements satisfying predicate into a new array, preserving order.\nT[?].u array_filter<T>(fixed T[?].m source, int(T).m predicate) {\n\tint length = len(source);\n\tT[?] result = rt.new(T[?]);\n\tfor (int i = 0; i < length; i++) if (predicate(source[i])) push(result, run.share_value(source[i]));\n\treturn result;\n}\n// fold elements from left to right, starting with initial; an empty array\n// returns initial without calling combine.\nA array_reduce<T,A>(fixed T[?].m source, A initial, A(A,T).m combine) {\n\tint length = len(source);\n\tfor (int i = 0; i < length; i++) initial = combine(initial, source[i]);\n\treturn initial;\n}\n\nrun.method(\"find\", array_find);\nrun.method(\"contains\", array_contains);\nrun.method(\"find_if\", array_find_if);\nrun.method(\"any\", array_any);\nrun.method(\"all\", array_all);\nrun.method(\"count\", array_count);\nrun.method(\"map\", array_map);\nrun.method(\"filter\", array_filter);\nrun.method(\"reduce\", array_reduce);\n";
-	return 0;
-}
-// ---- end embedded std library ----
-// ---- embedded icon library (generated by src/tools/embed.sh from src/lib/icon.zc; do not edit) ----
-bstr icon_part(int i) {
-	if (i == 0) return b"namespace icon;\ninclude rt, run;\n\n// structured runtime transformations of compiler token lists.\n// token storage follows run.tokens: count, then kind, value and source line.\n// edits create independent lists; publication recompiles a function only after\n// delimiter validation. captures match complete balanced token ranges.\n\nint icon_error;\n\nint icon_eq(word* a, int ai, word* b, int bi, int n) {\n\tint i = 0;\n\twhile (i < n) {\n\t\tif (a[1 + (ai + i) * 3] != b[1 + (bi + i) * 3] || a[2 + (ai + i) * 3] != b[2 + (bi + i) * 3]) return 0;\n\t\ti++;\n\t}\n\treturn 1;\n}\nint icon_value(word* q, int i) { if (i < 0 || i >= q[0]) return 0; return q[2 + i * 3]; }\nint icon_kind(word* q, int i) { if (i < 0 || i >= q[0]) return 0; return q[1 + i * 3]; }\nint icon_is(word* q, int i, char* s) {\n\tint kind = run.T_OP; if (s[0] >= 'a' && s[0] <= 'z') kind = run.T_ID;\n\treturn icon_kind(q, i) == kind && icon_value(q, i) == run.intern(s);\n}\nint icon_open(int v) { return v == run.intern(\"(\") || v == run.intern(\"[\") || v == run.intern(\"{\"); }\nint icon_close(int v) { return v == run.intern(\")\") || v == run.intern(\"]\") || v == run.intern(\"}\"); }\nint icon_pair(int a, int b) {\n\treturn (a == run.intern(\"(\") && b == run.intern(\")\")) || (a == run.intern(\"[\") && b == run.intern(\"]\")) || (a == run.intern(\"{\") && b == run.intern(\"}\"));\n}\nint icon_declaration(word* q, int start, int binding) {\n\tint first = icon_value(q, start), i = start;\n\tif (icon_kind(q, start) != run.T_ID || (first != run.intern(\"let\") && first != run.intern(\"const\") && !run.istypename(first))) return 0;\n\twhile (i < binding) { if (icon_is(q, i, \"(\") || icon_is(q, i, \"=\")) return 0; i++; }\n\treturn binding > start;\n}\n// locate a simple declaration at a statement boundary, including nested blocks.\n// result records [type start, binding position, semicolon, statement start].\nint icon_locate_declaration(word* q, int id, word* result) {\n\tint start = 0, i, depth, v, binding, comma, type_start;\n\twhile (start < q[0]) {\n\t\tif (start && !icon_is(q, start - 1, \";\") && !icon_is(q, start - 1, \"{\") && !icon_is(q, start - 1, \"}\")) { start++; continue; }\n\t\ttype_start = start; if (icon_is(q, type_start, \"const\")) type_start++;\n\t\tif (icon_kind(q, type_start) != run.T_ID || (!icon_is(q, type_start, \"let\") && !run.istypename(icon_value(q, type_start)))) { start++; continue; }\n\t\ti = type_start; depth = 0; binding = -1; comma = 0;\n\t\twhile (i < q[0]) {\n\t\t\tv = icon_value(q, i);\n\t\t\tif (!depth && v == id && icon_kind(q, i) == run.T_ID && binding < 0 && icon_declaration(q, type_start, i) && (icon_is(q, i + 1, \"=\") || icon_is(q, i + 1, \";\") || icon_is(q, i + 1, \",\") || icon_is(q, i + 1, \"(\"))) binding = i;\n\t\t\tif (icon_kind(q, i) == run.T_OP) {\n\t\t\t\tif (icon_open(v)) depth++;\n\t\t\t\telse if (icon_close(v)) { if (!depth) break; depth--; }\n\t\t\t\tif (!depth && v == run.intern(\",\")) comma = 1;\n\t\t\t\tif (!depth && v == run.intern(\";\")) {\n\t\t\t\t\tif (binding >= 0) {\n\t\t\t\t\t\tif (comma || icon_is(q, binding + 1, \"(\")) return 0;\n\t\t\t\t\t\tresult[0] = type_start; result[1] = bindin";
-	if (i == 1) return b"g; result[2] = i; result[3] = start; return 1;\n\t\t\t\t\t}\n\t\t\t\t\tbreak;\n\t\t\t\t}\n\t\t\t}\n\t\t\ti++;\n\t\t}\n\t\tstart++;\n\t}\n\treturn 0;\n}\nint icon_balanced(word* q, int a, int b) {\n\tword* stack = rt.new(b - a + 1); int n = 0, i = a, v, valid = 1;\n\twhile (i < b) {\n\t\tv = icon_value(q, i);\n\t\tif (icon_kind(q, i) == run.T_OP) {\n\t\t\tif (icon_open(v)) { stack[n] = v; n++; }\n\t\t\telse if (icon_close(v)) { if (!n || !icon_pair(stack[n - 1], v)) { valid = 0; break; } n--; }\n\t\t}\n\t\ti++;\n\t}\n\tif (n) valid = 0;\n\trt.free(stack);\n\treturn valid;\n}\nword* .u icon_slice(word* q, int a, int b) {\n\tword* r = rt.new(1 + (b - a) * 3); int i = 0; r[0] = b - a;\n\twhile (i < (b - a) * 3) { r[1 + i] = q[1 + a * 3 + i]; i++; }\n\treturn r;\n}\nword* .u icon_splice(word* q, int a, int b, word* insert) {\n\tint n = q[0] - (b - a) + insert[0], i = 0, j = 0;\n\tword* r = rt.new(1 + n * 3); r[0] = n;\n\twhile (i < a * 3) { r[1 + j] = q[1 + i]; i++; j++; }\n\ti = 0; while (i < insert[0] * 3) { r[1 + j] = insert[1 + i]; i++; j++; }\n\ti = b * 3; while (i < q[0] * 3) { r[1 + j] = q[1 + i]; i++; j++; }\n\treturn r;\n}\n// capture classes use integer literals, identifiers, expressions, statements\n// or blocks. a named capture records its exact token range for substitution.\nint icon_class(int name) {\n\tif (name == run.intern(\"int\")) return 1;\n\tif (name == run.intern(\"name\")) return 2;\n\tif (name == run.intern(\"expr\")) return 3;\n\tif (name == run.intern(\"stmt\")) return 4;\n\tif (name == run.intern(\"block\")) return 5;\n\treturn 0;\n}\nint icon_pattern(word* q) {\n\tint i = 0;\n\tif (!q || q[0] <= 0 || !icon_balanced(q, 0, q[0])) return 0;\n\twhile (i < q[0]) {\n\t\tif (icon_is(q, i, \"$\")) {\n\t\t\tif (icon_kind(q, i + 1) != run.T_ID || !icon_class(icon_value(q, i + 1))) return 0;\n\t\t\ti += 2;\n\t\t\tif (icon_is(q, i, \":\")) { if (icon_kind(q, i + 1) != run.T_ID || icon_class(icon_value(q, i + 1))) return 0; i += 2; }\n\t\t} else i++;\n\t}\n\treturn 1;\n}\nint icon_precedence(int name) {\n\tif (name == run.intern(\"||\")) return 1;\n\tif (name == run.intern(\"&&\")) return 2;\n\tif (name == run.intern(\"|\")) return 3;\n\tif (name == run.intern(\"^\")) return 4;\n\tif (name == run.intern(\"&\")) return 5;\n\tif (name == run.intern(\"==\") || name == run.intern(\"!=\")) return 6;\n\tif (name == run.intern(\"<\") || name == run.intern(\"<=\") || name == run.intern(\">\") || name == run.intern(\">=\")) return 7;\n\tif (name == run.intern(\"<<\") || name == run.intern(\">>\")) return 8;\n\tif (name == run.intern(\"+\") || name == run.intern(\"-\")) return 9;\n\tif (name == run.intern(\"*\") || name == run.intern(\"/\") || name == run.intern(\"%\")) return 10;\n\treturn 0;\n}\n// recognize expression structure before matching a variable-length capture.\n// this excludes statement keywords and incomplete operator sequences.\nint icon_expression(word* q, int start, int end, int minimum) {\n\tint i = start, v, kind, priority, next;\n\tif (i >= end) return -1;\n\tv = icon_value(q, i); kind = icon_kind(q, i);\n\tif (kind == run.T_OP && (v == run.intern(\"!\") || v == run.intern(\"~\") || v == run.intern(\"+\") || v == run.intern(\"-\") || v == run.intern(\"*";
-	if (i == 2) return b"\") || v == run.intern(\"&\"))) {\n\t\ti = icon_expression(q, i + 1, end, 11); if (i < 0) return -1;\n\t} else if (icon_is(q, i, \"(\")) {\n\t\ti = icon_expression(q, i + 1, end, 1); if (i < 0 || !icon_is(q, i, \")\")) return -1; i++;\n\t} else if (kind == run.T_NUM || kind == run.T_FLT || kind == run.T_STR || kind == run.T_BSTR || kind == run.T_ID) {\n\t\tif (kind == run.T_ID && (v == run.intern(\"return\") || v == run.intern(\"let\") || v == run.intern(\"if\") || v == run.intern(\"while\") || v == run.intern(\"for\") || v == run.intern(\"else\") || v == run.intern(\"break\") || v == run.intern(\"continue\") || v == run.intern(\"do\") || v == run.intern(\"switch\") || v == run.intern(\"const\"))) return -1;\n\t\ti++;\n\t} else return -1;\n\twhile (i < end) {\n\t\tif (icon_is(q, i, \"(\") || icon_is(q, i, \"[\")) {\n\t\t\tv = icon_value(q, i); i++;\n\t\t\tif (v != run.intern(\"(\") || !icon_is(q, i, \")\")) {\n\t\t\t\twhile (1) {\n\t\t\t\t\ti = icon_expression(q, i, end, 1); if (i < 0) return -1;\n\t\t\t\t\tif (v == run.intern(\"(\") && icon_is(q, i, \",\")) { i++; continue; } break;\n\t\t\t\t}\n\t\t\t}\n\t\t\tif (i >= end || icon_kind(q, i) != run.T_OP || !icon_pair(v, icon_value(q, i))) return -1; i++; continue;\n\t\t}\n\t\tif (icon_is(q, i, \".\")) { if (i + 1 >= end || icon_kind(q, i + 1) != run.T_ID) return -1; i += 2; continue; }\n\t\tif (icon_is(q, i, \"++\") || icon_is(q, i, \"--\")) { i++; continue; }\n\t\tif (minimum == 1 && icon_is(q, i, \"?\")) {\n\t\t\ti = icon_expression(q, i + 1, end, 1); if (i < 0 || !icon_is(q, i, \":\")) return -1;\n\t\t\ti = icon_expression(q, i + 1, end, 1); if (i < 0) return -1; continue;\n\t\t}\n\t\tpriority = 0; if (icon_kind(q, i) == run.T_OP) priority = icon_precedence(icon_value(q, i)); if (!priority || priority < minimum) break;\n\t\tnext = icon_expression(q, i + 1, end, priority + 1); if (next < 0) return -1; i = next;\n\t}\n\treturn i;\n}\nint icon_range(word* q, int a, int b, int kind) {\n\tif (a < 0 || a >= b || b > q[0]) return 0;\n\tif (kind == 1) return b == a + 1 && icon_kind(q, a) == run.T_NUM;\n\tif (kind == 2) return b == a + 1 && icon_kind(q, a) == run.T_ID;\n\tif (kind == 3) return icon_expression(q, a, b, 1) == b;\n\tif (kind == 5) return icon_is(q, a, \"{\") && icon_mate(q, a) == b - 1;\n\tif (kind == 4) return icon_statement_end(q, a) == b;\n\treturn icon_expression(q, a, b, 1) == b;\n}\n// recursively match a pattern with backtracking at balanced capture boundaries.\n// captures contain count followed by [name, start, end, class] records.\nint icon_match(word* q, int at, word* p, int pi, word* caps) {\n\tint kind, name, next, end, old, i;\n\tif (pi == p[0]) return at + 1;\n\tif (at >= q[0]) return 0;\n\tif (!icon_is(p, pi, \"$\")) {\n\t\tif (!icon_eq(q, at, p, pi, 1)) return 0;\n\t\treturn icon_match(q, at + 1, p, pi + 1, caps);\n\t}\n\tif (pi + 1 >= p[0]) return 0;\n\tname = icon_value(p, pi + 1); kind = icon_class(name); next = pi + 2;\n\tif (!kind) return 0;\n\tif (icon_is(p, next, \":\")) { name = icon_value(p, next + 1); next += 2; if (!name) return 0; }\n\telse name = 0;\n\told = caps[0]; end = at + 1;\n\tif (kind == 4) end = icon_statement_end(q, at);\n\tif (kind == 5) { if (!ic";
-	if (i == 3) return b"on_is(q, at, \"{\")) return 0; end = icon_mate(q, at) + 1; }\n\tif (end <= at) return 0;\n\twhile (end <= q[0]) {\n\t\tif (icon_range(q, at, end, kind)) {\n\t\t\ti = 0;\n\t\t\twhile (i < old) {\n\t\t\t\tif (name && caps[1 + i * 4] == name) {\n\t\t\t\t\tif (end - at != caps[3 + i * 4] - caps[2 + i * 4] || !icon_eq(q, at, q, caps[2 + i * 4], end - at)) break;\n\t\t\t\t}\n\t\t\t\ti++;\n\t\t\t}\n\t\t\tif (i == old) {\n\t\t\t\tcaps[0] = old + 1; caps[1 + old * 4] = name; caps[2 + old * 4] = at; caps[3 + old * 4] = end; caps[4 + old * 4] = kind;\n\t\t\t\ti = icon_match(q, end, p, next, caps);\n\t\t\t\tif (i) return i;\n\t\t\t\tcaps[0] = old;\n\t\t\t}\n\t\t}\n\t\tif (kind != 3) break;\n\t\tend++;\n\t}\n\treturn 0;\n}\nint icon_capture(word* caps, int name, int ordinal) {\n\tint c = 0, kind = icon_class(name), k = 0;\n\twhile (c < caps[0]) {\n\t\tif (!kind) { if (caps[1 + c * 4] == name) return c + 1; }\n\t\telse if (caps[4 + c * 4] == kind) { if (k == ordinal) return c + 1; k++; }\n\t\tc++;\n\t}\n\treturn 0;\n}\nword* .u icon_expand(word* q, word* replacement, word* caps) {\n\tint n = 0, i = 0, j = 0, c, name, kind, k, seen[6], a, b;\n\tk = 0; while (k < 6) { seen[k] = 0; k++; }\n\twhile (i < replacement[0]) {\n\t\tif (icon_is(replacement, i, \"$\")) {\n\t\t\tif (icon_kind(replacement, i + 1) != run.T_ID) { icon_error = 3; return 0; }\n\t\t\tname = icon_value(replacement, i + 1); kind = icon_class(name); c = icon_capture(caps, name, seen[kind]);\n\t\t\tif (!c) { icon_error = 3; return 0; } c--;\n\t\t\tn += caps[3 + c * 4] - caps[2 + c * 4]; if (kind) seen[kind]++; i += 2;\n\t\t} else { n++; i++; }\n\t}\n\tword* r = rt.new(1 + n * 3); i = 0;\n\tk = 0; while (k < 6) { seen[k] = 0; k++; }\n\twhile (i < replacement[0]) {\n\t\tif (icon_is(replacement, i, \"$\")) {\n\t\t\tname = icon_value(replacement, i + 1); kind = icon_class(name); c = icon_capture(caps, name, seen[kind]) - 1;\n\t\t\tif (kind) seen[kind]++;\n\t\t\ta = caps[2 + c * 4] * 3; b = caps[3 + c * 4] * 3;\n\t\t\twhile (a < b) { r[1 + j] = q[1 + a]; a++; j++; }\n\t\t\ti += 2;\n\t\t} else {\n\t\t\tk = 0; while (k < 3) { r[1 + j] = replacement[1 + i * 3 + k]; j++; k++; } i++;\n\t\t}\n\t}\n\tr[0] = j / 3;\n\tif (!icon_balanced(r, 0, r[0])) { rt.free(r); icon_error = 1; return 0; }\n\treturn r;\n}\n\n// resumable frames retain their own token list and explicit binding maps.\n// [tokens, position, state, result, error, locals, globals, blocks, steps].\n\n// locate a binding in a frame map by its interned name.\nint icon_binding(word map, int name) {\n\twhile (map) { if (map[0] == name) return map; map = map[2]; }\n\treturn 0;\n}\nint icon_read(word binding) { if (binding[3]) return *binding[3]; return binding[1]; }\nint icon_store(word*.m frame, int column, int name, int value) {\n\tword entry = icon_binding(frame[column], name);\n\tif (!entry) {\n\t\tword* node = rt.new(4); node[0] = name; node[1] = value; node[2] = frame[column]; node[3] = 0; frame[column] = node; return value;\n\t}\n\tentry[1] = value; if (entry[3]) *entry[3] = value; return value;\n}\nint icon_declare(word*.m frame, int name, int value) {\n\tword* node = rt.new(4); node[0] = name; node[1] = value; node[2] = frame[5]; node[3] = 0; frame[5] = no";
-	if (i == 4) return b"de; return value;\n}\nint icon_fail(word frame) { frame[2] = 2; frame[4] = 5; icon_error = 5; return 0; }\nint icon_end(word* q, int start) {\n\tint depth = 0, i = start, v;\n\twhile (i < q[0]) {\n\t\tv = icon_value(q, i);\n\t\tif (icon_kind(q, i) == run.T_OP) {\n\t\t\tif (icon_open(v)) depth++;\n\t\t\telse if (icon_close(v)) { if (!depth) return i; depth--; }\n\t\t\tif (!depth && v == run.intern(\";\")) return i;\n\t\t}\n\t\ti++;\n\t}\n\treturn i;\n}\nint icon_mate(word* q, int start) {\n\tint depth = 1, i = start + 1, v;\n\twhile (i < q[0]) {\n\t\tv = icon_value(q, i);\n\t\tif (icon_kind(q, i) == run.T_OP) {\n\t\t\tif (icon_open(v)) depth++; else if (icon_close(v)) depth--;\n\t\t\tif (!depth) return i;\n\t\t}\n\t\ti++;\n\t}\n\treturn -1;\n}\n// find one statement boundary; control-flow captures require braced bodies.\nint icon_statement_end(word* q, int start) {\n\tint close, end;\n\tif (icon_is(q, start, \"{\")) { close = icon_mate(q, start); if (close < 0) return -1; return close + 1; }\n\tif (icon_is(q, start, \"if\") || icon_is(q, start, \"while\")) {\n\t\tif (!icon_is(q, start + 1, \"(\")) return -1;\n\t\tclose = icon_mate(q, start + 1);\n\t\tif (close < 0 || !icon_is(q, close + 1, \"{\")) return -1;\n\t\tend = icon_mate(q, close + 1); if (end < 0) return -1; end++;\n\t\tif (icon_is(q, start, \"if\") && icon_is(q, end, \"else\")) {\n\t\t\tif (!icon_is(q, end + 1, \"{\")) return -1;\n\t\t\tclose = icon_mate(q, end + 1); if (close < 0) return -1; return close + 1;\n\t\t}\n\t\treturn end;\n\t}\n\tend = icon_end(q, start);\n\tif (!icon_is(q, end, \";\")) return -1;\n\treturn end + 1;\n}\n// construct a compiler return body in one allocation, retaining source lines.\nword* .u icon_eval_tokens(word* q, int start, int end) {\n\tint count = end - start;\n\tword* expr = rt.new(7 + count * 3); expr[0] = count + 2;\n\texpr[1] = run.T_ID; expr[2] = run.intern(\"return\"); expr[3] = 1;\n\tif (count) rt.copy_w(expr + 4, q + 1 + start * 3, count * 3);\n\texpr[4 + count * 3] = run.T_OP; expr[5 + count * 3] = run.intern(\";\"); expr[6 + count * 3] = 1;\n\treturn expr;\n}\n// scalar frame substitution cannot preserve lvalue operations or implicit\n// program-global reads. reject these before compiling or executing a range.\nint icon_frame_expression(word frame, int start, int end) {\n\tword* q = frame[0]; int i = start, s; word binding;\n\tif (!icon_range(q, start, end, 3)) return 0;\n\twhile (i < end) {\n\t\tif (icon_is(q, i, \"++\") || icon_is(q, i, \"--\")) return 0;\n\t\tif (icon_kind(q, i) == run.T_ID && !icon_is(q, i - 1, \".\")) {\n\t\t\tbinding = icon_binding(frame[5], icon_value(q, i));\n\t\t\tif (!binding) binding = icon_binding(frame[6], icon_value(q, i));\n\t\t\tif (!binding) {\n\t\t\t\ts = run.lookups(icon_value(q, i));\n\t\t\t\tif (s < 0 || (run.skind[s] != run.K_FN && run.skind[s] != run.K_CONST)) return 0;\n\t\t\t}\n\t\t}\n\t\ti++;\n\t}\n\treturn 1;\n}\nint icon_frame_eval(word frame, int start, int end) {\n\tword* expr = icon_eval_tokens(frame[0], start, end);\n\tint i = 1; word binding;\n\twhile (i < expr[0] - 1) {\n\t\tif (icon_kind(expr, i) == run.T_ID && !icon_is(expr, i - 1, \".\")) {\n\t\t\tbinding = icon_binding(frame[5], icon_value(expr, i));\n\t\t\tif (!bi";
-	if (i == 5) return b"nding) binding = icon_binding(frame[6], icon_value(expr, i));\n\t\t\tif (binding) { expr[1 + i * 3] = run.T_NUM; expr[2 + i * 3] = icon_read(binding); }\n\t\t}\n\t\ti++;\n\t}\n\tint result = run.eval(expr); rt.free(expr); return result;\n}\nint icon_block(word*.m frame, int open, int resume) {\n\tint close = icon_mate(frame[0], open);\n\tif (close < 0) return icon_fail(frame);\n\tword block = rt.new(4); block[0] = close; block[1] = resume; block[2] = frame[7]; block[3] = frame[5]; frame[7] = block; frame[1] = open + 1; return 1;\n}\n\nstruct icon {\n\t// the last transformation status: 0 success, 1 invalid delimiters,\n\t// 2 invalid range or declaration, 3 unresolved replacement capture,\n\t// 4 unavailable function metadata, 5 unsupported stepping syntax,\n\t// 6 rejected function publication.\n\tstatic int error() { return icon_error; }\n\t// check token delimiters without compiling or executing the list.\n\tstatic int validate(word* q) { icon_error = 0; if (!q || q[0] < 0 || !icon_balanced(q, 0, q[0])) { icon_error = 1; return 0; } return 1; }\n\t// return an independent token list with [start, end) replaced by insert.\n\tstatic word* .u splice(word* q, int start, int end, word* insert) {\n\t\ticon_error = 0;\n\t\tif (!q || !insert || q[0] < 0 || insert[0] < 0 || start < 0 || end < start || end > q[0]) { icon_error = 2; return 0; }\n\t\tword* r = icon_splice(q, start, end, insert);\n\t\tif (!icon_balanced(r, 0, r[0])) { rt.free(r); icon_error = 1; return 0; }\n\t\treturn r;\n\t}\n\t// replace each nonoverlapping pattern match. inserted tokens are not\n\t// searched again. the input and templates remain unchanged.\n\tstatic word* .u rewrite(word* q, word* pattern, word* replacement) {\n\t\ticon_error = 0;\n\t\tif (!q || q[0] < 0 || !replacement || replacement[0] < 0 || !icon_pattern(pattern) || !icon_balanced(q, 0, q[0])) { icon_error = 1; return 0; }\n\t\tword* result = icon_slice(q, 0, q[0]); word* caps = rt.new(1 + pattern[0] * 4); word* insert, next;\n\t\tint at = 0, end;\n\t\twhile (at < result[0]) {\n\t\t\tcaps[0] = 0; end = icon_match(result, at, pattern, 0, caps);\n\t\t\tif (!end) { at++; continue; }\n\t\t\tinsert = icon_expand(result, replacement, caps);\n\t\t\tif (!insert) { rt.free(result); rt.free(caps); return 0; }\n\t\t\tnext = icon_splice(result, at, end - 1, insert); at += insert[0];\n\t\t\trt.free(insert); rt.free(result); result = next;\n\t\t}\n\t\trt.free(caps); return result;\n\t}\n\t// transform retained function tokens and publish the compiled replacement.\n\t// references to the original entry continue to use the published version.\n\tstatic int find_replace(word function, word* pattern, word* replacement) {\n\t\ticon_error = 0;\n\t\tif (!replacement || replacement[0] < 0 || !icon_pattern(pattern)) { icon_error = 1; return 0; }\n\t\tword* q = run.function_tokens(function);\n\t\tif (!q) { icon_error = 4; return 0; }\n\t\tword* caps = rt.new(1 + pattern[0] * 4); int i = 0, end, count = 0;\n\t\twhile (i < q[0]) { caps[0] = 0; end = icon_match(q, i, pattern, 0, caps); if (end) { count++; i = end - 1; } else i++; }\n\t\trt.free(caps);\n\t\tif (!count) { rt.free(q); ";
-	if (i == 6) return b"return 0; }\n\t\tword* changed = icon.rewrite(q, pattern, replacement); rt.free(q);\n\t\tif (!changed) return 0;\n\t\tint published = run.replace_function(function, changed); rt.free(changed);\n\t\tif (!published) { icon_error = 6; return 0; }\n\t\treturn count;\n\t}\n\t// remove a complete declaration statement containing the requested name.\n\t// declarations containing multiple bindings are rejected to preserve them.\n\tstatic word* .u undeclare(word* q, char* name) {\n\t\ticon_error = 0;\n\t\tint declaration[4];\n\t\tif (!q || q[0] < 0 || !name || !icon_locate_declaration(q, run.intern(name), declaration)) { icon_error = 2; return 0; }\n\t\tword* empty = rt.new(1); empty[0] = 0;\n\t\tword* result = icon.splice(q, declaration[3], declaration[2] + 1, empty); rt.free(empty); return result;\n\t}\n\t// change the type of the first simple declaration of name.\n\tstatic word* .u change_type(word* q, char* name, word* type) {\n\t\ticon_error = 0;\n\t\tint declaration[4];\n\t\tif (!q || q[0] < 0 || !name || !icon_locate_declaration(q, run.intern(name), declaration)) { icon_error = 2; return 0; }\n\t\treturn icon.splice(q, declaration[0], declaration[1], type);\n\t}\n\t// insert a scoped statement block at the given token boundary.\n\tstatic word* .u insert_block(word* q, int at, word* body) {\n\t\ticon_error = 0;\n\t\tif (!q || !body || body[0] < 0 || at < 0 || at > q[0]) { icon_error = 2; return 0; }\n\t\tword* block = rt.new(7 + body[0] * 3); int i = 0; block[0] = body[0] + 2;\n\t\tblock[1] = run.T_OP; block[2] = run.intern(\"{\"); block[3] = 1;\n\t\twhile (i < body[0] * 3) { block[4 + i] = body[1 + i]; i++; }\n\t\tblock[4 + i] = run.T_OP; block[5 + i] = run.intern(\"}\"); block[6 + i] = 1;\n\t\tword* result = icon.splice(q, at, at, block); rt.free(block); return result;\n\t}\n\t// evaluate a selected expression using the compiler rather than a text\n\t// evaluator. the range must contain one complete expression.\n\tstatic int calculate(word* q, int start, int end) {\n\t\ticon_error = 0;\n\t\tif (!q || start < 0 || end > q[0] || !icon_range(q, start, end, 3)) { icon_error = 2; return 0; }\n\t\tword* expr = icon_eval_tokens(q, start, end);\n\t\tint value = run.eval(expr); rt.free(expr); return value;\n\t}\n\t// start a resumable evaluation with independent tokens and binding storage.\n\t// stepping executes statements through the compiler; no native frame is\n\t// suspended or inspected. scalar bindings are visible between statements.\n\tstatic word* .u begin(word* q) {\n\t\tif (!icon.validate(q)) { icon_error = 1; return 0; }\n\t\tword* frame = rt.new(9); int i = 0; while (i < 9) { frame[i] = 0; i++; } frame[0] = icon_slice(q, 0, q[0]); return frame;\n\t}\n\t// create an explicit frame from a function's retained body. argument values\n\t// are supplied through set_local before stepping starts.\n\tstatic word* .u begin_function(int function) {\n\t\tword* q = run.function_tokens(function);\n\t\tif (!q) { icon_error = 4; return 0; }\n\t\tword* frame = icon.begin(q); rt.free(q); return frame;\n\t}\n\t// set an isolated global binding, or update storage explicitly bound to it.\n\tstatic int set_gl";
-	if (i == 7) return b"obal(word frame, char* name, int value) { icon_error = 0; return icon_store(frame, 6, run.intern(name), value); }\n\t// update the innermost local binding, creating a binding when absent.\n\tstatic int set_local(word frame, char* name, int value) { icon_error = 0; return icon_store(frame, 5, run.intern(name), value); }\n\t// bind one existing scalar global explicitly. reads observe its current\n\t// value, and subsequent frame assignments update its program storage.\n\tstatic int bind_global(word frame, char* name) {\n\t\tint s = run.lookups(name); icon_error = 0;\n\t\tif (s < 0 || run.skind[s] != run.K_GVAR) { icon_error = 2; return 0; }\n\t\tword type = run.stype[s];\n\t\tif (type && type != run.tint && type != run.tword) { icon_error = 2; return 0; }\n\t\ticon_store(frame, 6, run.intern(name), *run.sval[s]);\n\t\tword binding = icon_binding(frame[6], run.intern(name)); binding[3] = run.sval[s]; return 1;\n\t}\n\t// read the innermost local binding; a missing binding sets status 2.\n\tstatic int local(word frame, char* name) { icon_error = 0; word b = icon_binding(frame[5], run.intern(name)); if (!b) { icon_error = 2; return 0; } return icon_read(b); }\n\t// read an isolated or explicitly connected global binding.\n\tstatic int global(word frame, char* name) { icon_error = 0; word b = icon_binding(frame[6], run.intern(name)); if (!b) { icon_error = 2; return 0; } return icon_read(b); }\n\t// frame state: 0 resumable, 1 complete, 2 unsupported statement.\n\tstatic int state(word frame) { return frame[2]; }\n\t// the returned value after completion; zero before a return is executed.\n\tstatic int result(word frame) { return frame[3]; }\n\t// token index of the next statement or control-flow decision.\n\tstatic int position(word frame) { return frame[1]; }\n\t// number of executed statements and control-flow decisions.\n\tstatic int steps(word frame) { return frame[8]; }\n\t// number of retained local binding records, including active shadowed records.\n\tstatic int local_count(word frame) { word b = frame[5]; int n = 0; while (b) { n++; b = b[2]; } return n; }\n\t// interned name of a local record; zero when index is outside the map.\n\tstatic char* local_name(word frame, int index) { word b = frame[5]; while (b && index > 0) { index--; b = b[2]; } if (!b || index < 0) return 0; return b[0]; }\n\t// execute one statement or control-flow decision. returns 1 after progress,\n\t// 0 after completion or an unsupported statement. blocks, if and while\n\t// require braces; declarations contain one scalar binding.\n\tstatic int step(word frame) {\n\t\tif (!frame || frame[2]) return 0;\n\t\ticon_error = 0;\n\t\tword* q = frame[0]; int at = frame[1], end, name, value, column = 5, v, close, open, alternate;\n\t\tword block, binding;\n\t\twhile (frame[7] && at == frame[7][0]) {\n\t\t\tblock = frame[7];\n\t\t\twhile (frame[5] != block[3]) { binding = frame[5]; frame[5] = binding[2]; rt.free(binding); }\n\t\t\tat = block[1]; frame[7] = block[2]; rt.free(block); frame[1] = at;\n\t\t}\n\t\tif (at >= q[0]) { frame[2] = 1; return 0; }\n\t\tframe[8]++;\n\t\tif (icon_is(q";
-	if (i == 8) return b", at, \";\")) { frame[1] = at + 1; return 1; }\n\t\tif (icon_is(q, at, \"{\")) { close = icon_mate(q, at); return icon_block(frame, at, close + 1); }\n\t\tif (icon_is(q, at, \"if\") || icon_is(q, at, \"while\")) {\n\t\t\tif (!icon_is(q, at + 1, \"(\")) return icon_fail(frame);\n\t\t\tclose = icon_mate(q, at + 1); open = close + 1;\n\t\t\tif (close < 0 || !icon_is(q, open, \"{\")) return icon_fail(frame);\n\t\t\tend = icon_mate(q, open); if (end < 0) return icon_fail(frame);\n\t\t\talternate = end + 1;\n\t\t\tif (icon_is(q, at, \"if\") && icon_is(q, alternate, \"else\")) {\n\t\t\t\tif (!icon_is(q, alternate + 1, \"{\")) return icon_fail(frame);\n\t\t\t}\n\t\t\tif (!icon_frame_expression(frame, at + 2, close)) return icon_fail(frame);\n\t\t\tvalue = icon_frame_eval(frame, at + 2, close);\n\t\t\tif (icon_is(q, at, \"while\")) { if (value) return icon_block(frame, open, at); frame[1] = end + 1; return 1; }\n\t\t\tif (icon_is(q, alternate, \"else\")) {\n\t\t\t\tclose = icon_mate(q, alternate + 1);\n\t\t\t\tif (value) return icon_block(frame, open, close + 1);\n\t\t\t\treturn icon_block(frame, alternate + 1, close + 1);\n\t\t\t}\n\t\t\tif (value) return icon_block(frame, open, end + 1);\n\t\t\tframe[1] = end + 1; return 1;\n\t\t}\n\t\tend = icon_end(q, at);\n\t\tif (end >= q[0] || !icon_is(q, end, \";\")) return icon_fail(frame);\n\t\tif (icon_is(q, at, \"return\")) {\n\t\t\tframe[3] = 0;\n\t\t\tif (end > at + 1) { if (!icon_frame_expression(frame, at + 1, end)) return icon_fail(frame); frame[3] = icon_frame_eval(frame, at + 1, end); }\n\t\t\tframe[1] = end + 1; frame[2] = 1; return 1;\n\t\t}\n\t\tif (icon_is(q, at, \"let\") || icon_is(q, at, \"int\") || icon_is(q, at, \"word\")) {\n\t\t\tif (icon_kind(q, at + 1) != run.T_ID) return icon_fail(frame);\n\t\t\tname = icon_value(q, at + 1); value = 0;\n\t\t\tif (end > at + 2) { if (!icon_is(q, at + 2, \"=\") || !icon_frame_expression(frame, at + 3, end)) return icon_fail(frame); value = icon_frame_eval(frame, at + 3, end); }\n\t\t\ticon_declare(frame, name, value); frame[1] = end + 1; return 1;\n\t\t}\n\t\tname = icon_value(q, at); binding = icon_binding(frame[5], name);\n\t\tif (!binding) { binding = icon_binding(frame[6], name); column = 6; }\n\t\tif (binding && icon_kind(q, at) == run.T_ID) {\n\t\t\tv = icon_value(q, at + 1);\n\t\t\tif (end == at + 2 && (v == run.intern(\"++\") || v == run.intern(\"--\"))) {\n\t\t\t\tvalue = icon_read(binding) + 1; if (v == run.intern(\"--\")) value = icon_read(binding) - 1;\n\t\t\t} else {\n\t\t\t\tif (v != run.intern(\"=\") && v != run.intern(\"+=\") && v != run.intern(\"-=\") && v != run.intern(\"*=\") && v != run.intern(\"/=\")) return icon_fail(frame);\n\t\t\t\tif (!icon_frame_expression(frame, at + 2, end)) return icon_fail(frame);\n\t\t\t\tvalue = icon_frame_eval(frame, at + 2, end);\n\t\t\t\tif (v == run.intern(\"+=\")) value = icon_read(binding) + value;\n\t\t\t\tif (v == run.intern(\"-=\")) value = icon_read(binding) - value;\n\t\t\t\tif (v == run.intern(\"*=\")) value = icon_read(binding) * value;\n\t\t\t\tif (v == run.intern(\"/=\")) value = icon_read(binding) / value;\n\t\t\t}\n\t\t\ticon_store(frame, column, name, value); frame[1] = end + 1; return 1;\n\t\t}\n\t\treturn icon_fail(frame);\n\t}\n\t// execute at most budg";
-	if (i == 9) return b"et statements. returning 0 leaves the frame resumable;\n\t// callers can inspect bindings, edit them, then continue with another budget.\n\tstatic int resume(word frame, int budget) { while (budget > 0 && !frame[2]) { icon.step(frame); budget--; } return frame[2]; }\n\t// release a frame and all storage it owns.\n\tstatic int close(.d frame) {\n\t\tword b, next; int column = 5;\n\t\twhile (column <= 7) { b = frame[column]; while (b) { next = b[2]; rt.free(b); b = next; } column++; }\n\t\trt.free(frame[0]); rt.free(frame); return 0;\n\t}\n}\n\n// public entry points for the icon namespace.\n\n// status of the most recent transformation or binding operation; see docs/ICON.md.\nint error() { return icon.icon.error(); }\n// check delimiter structure only; does not compile or execute tokens.\nint validate(word* q) { return icon.icon.validate(q); }\n// return a new token list with [start, end) replaced; caller owns the result.\nword* .u splice(word* q, int start, int end, word* insert) { return icon.icon.splice(q, start, end, insert); }\n// return a new list with nonoverlapping matches replaced; inputs remain unchanged.\nword* .u rewrite(word* q, word* pattern, word* replacement) { return icon.icon.rewrite(q, pattern, replacement); }\n// publish a transformed function body; returns matches, or 0 on no match or failure.\nint find_replace(word function, word* pattern, word* replacement) { return icon.icon.find_replace(function, pattern, replacement); }\n// remove the first complete single-binding declaration named name; caller owns the result.\nword* .u undeclare(word* q, char* name) { return icon.icon.undeclare(q, name); }\n// replace the type prefix of the first simple declaration named name; caller owns the result.\nword* .u change_type(word* q, char* name, word* type) { return icon.icon.change_type(q, name, type); }\n// insert a scoped block containing body at token boundary at; caller owns the result.\nword* .u insert_block(word* q, int at, word* body) { return icon.icon.insert_block(q, at, body); }\n// compile and evaluate the expression in [start, end); expression calls retain their effects.\nint calculate(word* q, int start, int end) { return icon.icon.calculate(q, start, end); }\n// create a frame with copied tokens and isolated bindings; caller closes the frame.\nword* .u begin(word* q) { return icon.icon.begin(q); }\n// create a frame from retained function tokens; set arguments as locals before stepping.\nword* .u begin_function(int function) { return icon.icon.begin_function(function); }\n// set an isolated global binding, creating it when absent; returns the stored value.\nint set_global(word frame, char* name, int value) { return icon.icon.set_global(frame, name, value); }\n// set the innermost local binding, creating it when absent; returns the stored value.\nint set_local(word frame, char* name, int value) { return icon.icon.set_local(frame, name, value); }\n// connect an int or word program global to the frame; later frame writes update it.\nint bind_global(word frame, char* name) { ret";
-	if (i == 10) return b"urn icon.icon.bind_global(frame, name); }\n// read a local binding; missing names return 0 and set error status 2.\nint local(word frame, char* name) { return icon.icon.local(frame, name); }\n// read a frame global binding; missing names return 0 and set error status 2.\nint global(word frame, char* name) { return icon.icon.global(frame, name); }\n// return frame state: 0 resumable, 1 complete, or 2 unsupported statement.\nint state(word frame) { return icon.icon.state(frame); }\n// return the value produced by return, or 0 before a return is executed.\nint result(word frame) { return icon.icon.result(frame); }\n// return the token index of the next statement or control-flow decision.\nint position(word frame) { return icon.icon.position(frame); }\n// return the number of statements and control-flow decisions executed.\nint steps(word frame) { return icon.icon.steps(frame); }\n// count retained local records, including shadowed records in active blocks.\nint local_count(word frame) { return icon.icon.local_count(frame); }\n// return the zero-based local record name, or 0 when index is out of range.\nchar* local_name(word frame, int index) { return icon.icon.local_name(frame, index); }\n// execute scalar declarations and assignments, standalone ++/--, return, blocks,\n// or braced if/else/while; direct program globals need bind_global first.\n// unsupported syntax sets error status 5.\nint step(word frame) { return icon.icon.step(frame); }\n// execute at most budget steps and return the frame state; frame bindings are scalar int/word values.\nint resume(word frame, int budget) { return icon.icon.resume(frame, budget); }\n// release the frame and owned storage; consumes frame and returns 0.\nint close(.d frame) { return icon.icon.close(d*frame); }\n";
-	return 0;
-}
-// ---- end embedded icon library ----
+// the source of the std and icon libraries, embedded when the compiler is built, so
+// `include std;` and `include icon;` need no file at run time.
+embed "src/lib/std.zc" as bstr std_embedded;
+embed "src/lib/icon.zc" as bstr icon_embedded;
+bstr std_source() { return std_embedded; }
+bstr icon_source() { return icon_embedded; }
diff --git a/src/core/core.c b/src/core/core.c
index 3a1d0ca..dc50644 100644
--- a/src/core/core.c
+++ b/src/core/core.c
@@ -58,13 +58,7 @@
 #include <sys/mman.h>
 #include <ucontext.h>
 #endif
-#ifdef USE_LSP_GENOME
-#include "lsp_genome.h"
-#elif defined(GENOME_H)
-#include GENOME_H
-#else
 #include "genome.h"
-#endif
 #include "memmap.h"
 #include "fops.h"
 #include "bops.h"
@@ -6208,7 +6202,7 @@ int main(int argc, char **argv)
 		fprintf(stderr, "zy: genome does not fit\n");
 		return 1;
 	}
-	memcpy(m + GORG, genome, sizeof genome);
+	for (int g = 0; g < GLEN; g++) m[GORG + g] = genome_word(g);
 	m[ZFP + 6] = FBOT; m[ZFP + 7] = FTOP; m[ZFP + 8] = 1024;
 #ifdef ZYJIT
 	{
diff --git a/src/core/genome.h b/src/core/genome.h
new file mode 100644
index 0000000..9d0ff96
--- /dev/null
+++ b/src/core/genome.h
@@ -0,0 +1,35 @@
+/* the genome: the image a core boots, embedded into the core when it is
+   compiled. an image is a file of little-endian 64-bit words placed at GORG,
+   as written by zc0 or by src/tools/build.zc and checked by mkgenome. the
+   build keeps every image in build/, never in the tree.
+
+   GENOME_FILE names the image. it defaults to "genome.bin" (or
+   "lsp_genome.bin" with USE_LSP_GENOME) and is found next to this header,
+   then in the directories given with --embed-dir, so that option selects
+   which image a core carries. the file needs a compiler with c23
+   #embed (clang 19 or gcc 15 and later).
+
+   no libc here: the microcore includes this on bare metal. */
+#ifndef GENOME_H_INCLUDED
+#define GENOME_H_INCLUDED
+#include <stdint.h>
+#ifndef GENOME_FILE
+#ifdef USE_LSP_GENOME
+#define GENOME_FILE "lsp_genome.bin"
+#else
+#define GENOME_FILE "genome.bin"
+#endif
+#endif
+static const unsigned char genome_image[] = {
+#embed GENOME_FILE
+};
+/* the image's length in words */
+#define GLEN ((int)(sizeof genome_image / 8))
+/* word i of the image, independent of the host's byte order */
+static int64_t genome_word(int i)
+{
+	const unsigned char *b = genome_image + (long)i * 8;
+	return (int64_t)((uint64_t)b[0] | (uint64_t)b[1] << 8 | (uint64_t)b[2] << 16 | (uint64_t)b[3] << 24
+		| (uint64_t)b[4] << 32 | (uint64_t)b[5] << 40 | (uint64_t)b[6] << 48 | (uint64_t)b[7] << 56);
+}
+#endif
diff --git a/src/core/memmap.h b/src/core/memmap.h
deleted file mode 100644
index cc768d4..0000000
--- a/src/core/memmap.h
+++ /dev/null
@@ -1,34 +0,0 @@
-/* generated by src/tools/genmap for the default profile. do not edit. */
-#ifndef MEMMAP_H
-#define MEMMAP_H
-#define PW 0x1D5000
-#define CODE_END 0x80000
-#define HEAP_LO 0x1D5000
-#define HEAP_HI 0x235000
-#define HEAP_GROW 1
-#ifndef MW
-#define MW 0x8000000
-#endif
-#if MW < HEAP_HI
-#error MW is below the end of the initial heap
-#endif
-#define ZFP 0x90000
-#ifdef GORG
-#if GORG != 0x114100
-#error genome GORG does not match this map
-#endif
-#else
-#define GORG 0x114100
-#endif
-#define FBOT 0x174100
-#define FTOP 0x1B4100
-#define RS0 0x1B4100
-#define MARK0 0x1C4100
-#define MARKN 0x8000
-#define DSLO 0x1CC100
-#define DSHI 0x1D4FF0
-#define DS0 DSHI
-#define SYSGATE (ZFP + 2)
-#define DSLIM (DSLO + 1100)
-#define RSLIM (MARK0 - 8)
-#endif
diff --git a/src/js/extract_genome.js b/src/js/extract_genome.js
deleted file mode 100644
index 4ef2c43..0000000
--- a/src/js/extract_genome.js
+++ /dev/null
@@ -1,93 +0,0 @@
-// converts the compiler genome and the memory map into the javascript vm's
-// layout files. everything it writes is generated, so it goes to build/js/ and
-// nothing is left in the tree.
-//
-//   node src/js/extract_genome.js [--genome PATH] [--map PATH] [--out DIR]
-//
-// the genome is the one make genome produced in build/core/genome.h, and the
-// map is src/core/memmap.h. outputs, in the out directory:
-//   genome.json   the genome words, for the vm that has no compiler inside it
-//   layout.ts     the map as typescript constants
-//   layout.js     the map as commonjs constants
-const fs = require('fs');
-const path = require('path');
-const root = path.join(__dirname, '..', '..');
-
-const args = process.argv.slice(2);
-const opt = (name) => {
-    const i = args.indexOf(name);
-    return i >= 0 && args[i + 1] ? args[i + 1] : null;
-};
-if (args.includes('--help') || args.includes('-h')) {
-    console.log([
-        'usage: node src/js/extract_genome.js [--genome PATH] [--map PATH] [--out DIR]',
-        'converts the compiler genome and memory map into the javascript layout files.',
-        'options:',
-        '  --genome PATH   the genome header to read; defaults to build/core/genome.h',
-        '  --map PATH      the memory map header to read; defaults to src/core/memmap.h',
-        '  --out DIR       where to write; defaults to build/js',
-        '  --help, -h      show this help and exit',
-    ].join('\n'));
-    process.exit(0);
-}
-const unknown = args.filter((a) => !['--genome', '--map', '--out'].includes(a));
-if (unknown.length) {
-    console.error('extract_genome: unexpected arguments: ' + unknown.join(' ') + '; use --help for usage');
-    process.exit(2);
-}
-
-const genomePath = opt('--genome') || path.join(root, 'build', 'core', 'genome.h');
-const mapPath = opt('--map') || path.join(__dirname, '..', 'core', 'memmap.h');
-const outDir = opt('--out') || path.join(root, 'build', 'js');
-
-if (!fs.existsSync(genomePath)) {
-    console.error('extract_genome: no genome at ' + genomePath + '; run `make genome` first');
-    process.exit(1);
-}
-fs.mkdirSync(outDir, { recursive: true });
-
-const text = fs.readFileSync(genomePath, 'utf8');
-const gorgMatch = text.match(/#define\s+GORG\s+(\d+)/);
-const glenMatch = text.match(/#define\s+GLEN\s+(\d+)/);
-
-const gorg = parseInt(gorgMatch[1], 10);
-const glen = parseInt(glenMatch[1], 10);
-
-const arrMatch = text.match(/genome\[\]\s*=\s*\{([\s\S]*?)\};/);
-if (!arrMatch) {
-    console.error('extract_genome: could not find the genome array in ' + genomePath);
-    process.exit(1);
-}
-
-const words = arrMatch[1]
-    .split(',')
-    .map(s => s.trim())
-    .filter(s => s.length > 0);
-
-console.log(`Parsed genome: GORG=${gorg}, GLEN=${words.length}`);
-
-if (words.length !== glen) throw new Error('genome length does not match GLEN');
-
-// the compiler's map, as typescript constants: the js vm reads them instead of
-// its own copies. the values are computed here, from the map.
-const { mapValues } = require('./mapvalues.js');
-const names = ['MW', 'PW', 'ZFP', 'GORG', 'DS0', 'DSLIM', 'RS0', 'RSLIM', 'SYSGATE', 'HEAP_LO', 'HEAP_HI'];
-const map = mapValues(mapPath, names);
-if (map.GORG !== gorg) throw new Error('genome GORG ' + gorg + ' is not the map GORG ' + map.GORG);
-
-const genomeJson = path.join(outDir, 'genome.json');
-fs.writeFileSync(genomeJson, JSON.stringify({ gorg, glen, words }));
-console.log('saved genome to ' + genomeJson);
-
-const lines = names.map(k => `    ${k}: ${map[k]},`).join('\n');
-const layoutTs = path.join(outDir, 'layout.ts');
-fs.writeFileSync(layoutTs,
-    '// generated by src/js/extract_genome.js from ' + path.relative(root, mapPath) + '. do not edit.\n' +
-    'export const MAP = {\n' + lines + '\n} as const;\n');
-console.log('saved the map to ' + layoutTs);
-
-const layoutJs = path.join(outDir, 'layout.js');
-fs.writeFileSync(layoutJs,
-    '// generated by src/js/extract_genome.js from ' + path.relative(root, mapPath) + '. do not edit.\n' +
-    'exports.MAP = ' + JSON.stringify(map, null, 4) + ';\n');
-console.log('saved the map to ' + layoutJs);
\ No newline at end of file
diff --git a/src/js/extract_lsp.js b/src/js/extract_lsp.js
index 14ee279..bdbcb3c 100644
--- a/src/js/extract_lsp.js
+++ b/src/js/extract_lsp.js
@@ -1,13 +1,12 @@
-// writes the language server's javascript image: the genome build/lsp/genome.h,
-// made by src/tools/mklsp.sh, and the map it was built for, read from
-// build/lsp/map/memmap.h. the vm needs the layout, because the server's map is
-// not the compiler's. the image is generated, so it goes to build/js/ and
-// nothing is left in the tree.
+// writes the language server's javascript image: build/js/lsp.bin, the server's
+// genome (build/lsp/lsp_genome.bin, made by src/tools/mklsp.sh), and
+// build/js/lsp.json, the map it was built for, read from build/lsp/memmap.h. the
+// vm needs the layout, because the server's map is not the compiler's. the image
+// is generated, so it goes to build/js/ and nothing is left in the tree.
 //
-//   node src/js/extract_lsp.js [--out PATH]
+//   node src/js/extract_lsp.js [--lsp DIR] [--out DIR]
 //
-// build the lsp first (`make lsp`, or src/tools/mklsp.sh); it needs
-// build/lsp/genome.h.
+// build the lsp first (`make lsp`, or src/tools/mklsp.sh).
 const fs = require('fs');
 const path = require('path');
 const root = path.join(__dirname, '..', '..');
@@ -15,42 +14,39 @@ const root = path.join(__dirname, '..', '..');
 const args = process.argv.slice(2);
 if (args.includes('--help') || args.includes('-h')) {
     console.log([
-        'usage: node src/js/extract_lsp.js [--out PATH]',
-        'converts the language server genome and its memory map into a javascript image.',
+        'usage: node src/js/extract_lsp.js [--lsp DIR] [--out DIR]',
+        'copies the language server genome beside a json description of its memory map.',
         'options:',
-        '  --out PATH   where to write; defaults to build/js/lsp.json',
+        '  --lsp DIR    the language server build to read; defaults to build/lsp',
+        '  --out DIR    where to write lsp.bin and lsp.json; defaults to build/js',
         '  --help, -h   show this help and exit',
     ].join('\n'));
     process.exit(0);
 }
-let out = path.join(root, 'build', 'js', 'lsp.json');
+let out = path.join(root, 'build', 'js'), lsp = path.join(root, 'build', 'lsp');
 for (let i = 0; i < args.length; i++) {
-    if (args[i] === '--out' && args[i + 1]) out = args[i + 1];
+    if (args[i] === '--out' && args[i + 1]) out = args[++i];
+    else if (args[i] === '--lsp' && args[i + 1]) lsp = args[++i];
     else {
         console.error('extract_lsp: unexpected arguments; use --help for usage');
         process.exit(2);
     }
 }
 
-const genomePath = path.join(root, 'build', 'lsp', 'genome.h');
-const mapPath = path.join(root, 'build', 'lsp', 'map', 'memmap.h');
+const genomePath = path.join(lsp, 'lsp_genome.bin');
+const mapPath = path.join(lsp, 'memmap.h');
 if (!fs.existsSync(genomePath)) {
     console.error('extract_lsp: no language server image at ' + genomePath + '; run `make lsp` first');
     process.exit(1);
 }
-const genome = fs.readFileSync(genomePath, 'utf8');
-
 const { mapValues } = require('./mapvalues.js');
 const layout = mapValues(mapPath, ['GORG', 'DS0', 'DSLIM', 'RS0', 'RSLIM', 'SYSGATE', 'ZFP', 'HEAP_LO', 'HEAP_HI']);
+const image = fs.readFileSync(genomePath);
+if (image.length % 8) throw new Error(genomePath + ' is not a whole number of words');
+const glen = image.length / 8;
 
-const gorg = parseInt(genome.match(/#define\s+GORG\s+(\d+)/)[1], 10);
-const glen = parseInt(genome.match(/#define\s+GLEN\s+(\d+)/)[1], 10);
-const arr = genome.match(/genome\[\]\s*=\s*\{([\s\S]*?)\};/);
-const words = arr[1].split(',').map(s => s.trim()).filter(s => s.length > 0);
-if (words.length !== glen) throw new Error('genome has ' + words.length + ' words, GLEN says ' + glen);
-if (gorg !== layout.GORG) throw new Error('genome GORG ' + gorg + ' is not the map GORG ' + layout.GORG);
-
-fs.mkdirSync(path.dirname(out), { recursive: true });
-fs.writeFileSync(out, JSON.stringify({ gorg, glen, layout, words }));
-console.log('wrote ' + path.relative(root, out) + ': genome ' + glen + ' words at ' + gorg +
-    ', heap ' + layout.HEAP_LO + '..' + layout.HEAP_HI);
\ No newline at end of file
+fs.mkdirSync(out, { recursive: true });
+fs.copyFileSync(genomePath, path.join(out, 'lsp.bin'));
+fs.writeFileSync(path.join(out, 'lsp.json'), JSON.stringify({ gorg: layout.GORG, glen, layout }));
+console.log('wrote ' + path.relative(root, path.join(out, 'lsp.bin')) + ': genome ' + glen + ' words at ' + layout.GORG +
+    ', heap ' + layout.HEAP_LO + '..' + layout.HEAP_HI);
diff --git a/src/js/layout.d.ts b/src/js/layout.d.ts
index 1e8c004..9a531eb 100644
--- a/src/js/layout.d.ts
+++ b/src/js/layout.d.ts
@@ -1,5 +1,5 @@
 // types for the map the javascript vm reads at runtime. the values are
-// generated by src/js/extract_genome.js into build/js/layout.js, which sits
+// generated by src/js/mklayout.js into build/js/layout.js, which sits
 // beside the compiled vm; this declaration is here so tinyvm.ts typechecks
 // without a generated file in the tree.
 export declare const MAP: {
diff --git a/src/js/mapvalues.js b/src/js/mapvalues.js
index f701ba2..bb6fc86 100644
--- a/src/js/mapvalues.js
+++ b/src/js/mapvalues.js
@@ -1,6 +1,6 @@
 // reads the values of a machine map from its memmap.h. the #define lines may use
 // other names and small sums (ZFP + 2, DSLO + 1100), so each value is evaluated
-// with its names substituted. shared by extract_genome.js and extract_lsp.js.
+// with its names substituted. shared by mklayout.js and extract_lsp.js.
 const fs = require('fs');
 
 function mapValues(mapPath, names) {
diff --git a/src/js/mklayout.js b/src/js/mklayout.js
new file mode 100644
index 0000000..cf95091
--- /dev/null
+++ b/src/js/mklayout.js
@@ -0,0 +1,61 @@
+// writes the javascript vm's view of a memory map: the map's constants as
+// typescript and commonjs modules. the vm reads its genome image itself, from
+// genome.bin beside tinyvm.js, so only the layout is generated here. everything
+// it writes is generated, so it goes to build/js/ and nothing is left in the tree.
+//
+//   node src/js/mklayout.js [--map PATH] [--out DIR]
+//
+// the map is the default one `make` generates in build/core/map/memmap.h.
+// outputs, in the out directory:
+//   layout.ts     the map as typescript constants
+//   layout.js     the map as commonjs constants
+const fs = require('fs');
+const path = require('path');
+const root = path.join(__dirname, '..', '..');
+
+const args = process.argv.slice(2);
+const opt = (name) => {
+    const i = args.indexOf(name);
+    return i >= 0 && args[i + 1] ? args[i + 1] : null;
+};
+if (args.includes('--help') || args.includes('-h')) {
+    console.log([
+        'usage: node src/js/mklayout.js [--map PATH] [--out DIR]',
+        'converts a memory map header into the javascript vm layout files.',
+        'options:',
+        '  --map PATH      the memory map header to read; defaults to build/core/map/memmap.h',
+        '  --out DIR       where to write; defaults to build/js',
+        '  --help, -h      show this help and exit',
+    ].join('\n'));
+    process.exit(0);
+}
+for (let i = 0; i < args.length; i += 2) {
+    if (!['--map', '--out'].includes(args[i]) || args[i + 1] === undefined) {
+        console.error('mklayout: unexpected arguments: ' + args.join(' ') + '; use --help for usage');
+        process.exit(2);
+    }
+}
+
+const mapPath = opt('--map') || path.join(root, 'build', 'core', 'map', 'memmap.h');
+const outDir = opt('--out') || path.join(root, 'build', 'js');
+if (!fs.existsSync(mapPath)) {
+    console.error('mklayout: no memory map at ' + mapPath + '; run `make` first');
+    process.exit(1);
+}
+fs.mkdirSync(outDir, { recursive: true });
+
+// the compiler's map, as constants: the js vm reads them instead of its own copies.
+const { mapValues } = require('./mapvalues.js');
+const names = ['MW', 'PW', 'ZFP', 'GORG', 'DS0', 'DSLIM', 'RS0', 'RSLIM', 'SYSGATE', 'HEAP_LO', 'HEAP_HI'];
+const map = mapValues(mapPath, names);
+
+const lines = names.map(k => `    ${k}: ${map[k]},`).join('\n');
+const layoutTs = path.join(outDir, 'layout.ts');
+fs.writeFileSync(layoutTs,
+    '// generated by src/js/mklayout.js from ' + path.relative(root, mapPath) + '. do not edit.\n' +
+    'export const MAP = {\n' + lines + '\n} as const;\n');
+const layoutJs = path.join(outDir, 'layout.js');
+fs.writeFileSync(layoutJs,
+    '// generated by src/js/mklayout.js from ' + path.relative(root, mapPath) + '. do not edit.\n' +
+    'exports.MAP = ' + JSON.stringify(map, null, 4) + ';\n');
+console.log('wrote ' + path.relative(root, layoutJs) + ' and layout.ts');
diff --git a/src/js/tinyvm.ts b/src/js/tinyvm.ts
index 4b4bc39..56fab70 100644
--- a/src/js/tinyvm.ts
+++ b/src/js/tinyvm.ts
@@ -10,7 +10,7 @@ declare const process: any, require: any, module: any, __dirname: string, Buffer
 const fs: any = typeof require === 'function' ? require('fs') : undefined;
 const path: any = typeof require === 'function' ? require('path') : undefined;
 
-// the compiler's map, computed from src/core/memmap.h at build time (build/js/layout.js)
+// the compiler's map, computed from build/core/map/memmap.h at build time (build/js/layout.js)
 import { MAP } from './layout';
 
 // float bits stay in vm words; arithmetic uses javascript's binary64 numbers.
@@ -257,6 +257,16 @@ export class TinyVM {
         }
     }
 
+    /** load an image file's bytes (little-endian 64-bit words, the format the c cores
+        #embed) at org. returns the number of words. */
+    public loadImage(bytes: Uint8Array, org: number = this.L.GORG): number {
+        if (bytes.length % 8) throw new RangeError('an image is a whole number of 64-bit words');
+        const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.length);
+        const n = bytes.length / 8;
+        for (let i = 0; i < n; i++) this.mem[org + i] = view.getBigInt64(i * 8, true);
+        return n;
+    }
+
     public getOutput(): string {
         return new TextDecoder().decode(new Uint8Array(this.outputBuffer));
     }
@@ -931,13 +941,13 @@ if (typeof require === 'function' && typeof module !== 'undefined' && require.ma
         process.stderr.write('tinyvm.js: unknown option ' + option + '; use --help for usage\n');
         process.exit(2);
     }
-    const genomePath = path.join(__dirname, 'genome.json');
+    const genomePath = path.join(__dirname, 'genome.bin');
     if (!fs.existsSync(genomePath)) {
-        console.error('Error: genome.json not found. Run extract_genome.js first.');
+        console.error('Error: genome.bin not found beside tinyvm.js. Run make js first.');
         process.exit(1);
     }
 
-    const genomeData = JSON.parse(fs.readFileSync(genomePath, 'utf8'));
+    const genome: Uint8Array = fs.readFileSync(genomePath);
     let inputSource = '';
 
     if (process.argv.length > 2) {
@@ -970,9 +980,9 @@ if (typeof require === 'function' && typeof module !== 'undefined' && require.ma
         onMessage: (msg: string) => process.stderr.write(msg)
     });
 
-    vm.loadGenome(genomeData.words, genomeData.gorg);
+    vm.loadImage(genome, GORG);
     vm.setInput(inputSource);
-    const code = vm.run(genomeData.gorg);
+    const code = vm.run(GORG);
     process.exit(code);
 }
 
diff --git a/src/lsp/server.zc b/src/lsp/server.zc
index a07e4d4..48fdf90 100644
--- a/src/lsp/server.zc
+++ b/src/lsp/server.zc
@@ -1057,8 +1057,15 @@ int doc_gap(int base, int from, int to) {
 	return 1;
 }
 // remove comment delimiters and optional line-leading stars; retain markdown.
+// the line comment emitted last: consecutive // lines are one paragraph, joined by a soft break
+int hct_doc = 0 - 1, hct_end, hct_hn;
+int hover_comment_adjacent(int base, int from, int to) {
+	int lines = 0, c;
+	while (from < to) { c = dc(base, from); if (c == 10) lines++; else if (c != 32 && c != 9 && c != 13) return 0; from++; }
+	return lines <= 1;
+}
 int hover_comment_text(int i, int index) {
-	int base = doff[i], o = hc_start[index] + 2, end = hc_end[index], bol = 1, c, before = hn;
+	int base = doff[i], o = hc_start[index] + 2, end = hc_end[index], bol = 1, c, before = hn, joined;
 	if (hc_kind[index] == 3) {
 		if (end >= o + 2 && dc(base, end - 2) == '*' && dc(base, end - 1) == '/') end = end - 2;
 		if (o < end && dc(base, o) == '*') o++;
@@ -1066,7 +1073,8 @@ int hover_comment_text(int i, int index) {
 	while (o < end && (dc(base, o) == 32 || dc(base, o) == 9 || dc(base, o) == 10 || dc(base, o) == 13)) o++;
 	while (end > o && (dc(base, end - 1) == 32 || dc(base, end - 1) == 9 || dc(base, end - 1) == 10 || dc(base, end - 1) == 13)) end--;
 	if (o == end) return 0;
-	hov_text("\n\n");
+	joined = hc_kind[index] != 3 && hct_doc == i && hct_hn == hn && hn > 0 && hover_comment_adjacent(base, hct_end, hc_start[index]);
+	if (joined) hov_put(10); else hov_text("\n\n");
 	while (o < end) {
 		if (bol && hc_kind[index] == 3) {
 			while (o < end && (dc(base, o) == 32 || dc(base, o) == 9)) o++;
@@ -1078,6 +1086,7 @@ int hover_comment_text(int i, int index) {
 		if (c != 13) hov_put(c);
 		if (c == 10) bol = 1;
 	}
+	if (hc_kind[index] != 3) { hct_doc = i; hct_end = hc_end[index]; hct_hn = hn; } else hct_doc = 0 - 1;
 	return hn - before;
 }
 // a trailing declaration comment belongs to its last name, not the next line.
@@ -2085,18 +2094,21 @@ int do_nav(int i, int refs) {
 }
 
 //: ---- the sources of this image ----
-//: the image carries the text of rt.zc, compiler.zc, server.zc, std.zc, icon.zc and core.zc (the
-//: pieces src/tools/embed.sh made), so the definition of a built-in has somewhere to go. each source is a document
+//: the image carries the text of rt.zc, compiler.zc, server.zc, std.zc, icon.zc and core.zc, embedded
+//: when the image is built, so the definition of a built-in has somewhere to go. each source is a document
 //: of its own at tinyvm:/NAME.zc, which the editor shows read only and can ask for with zc/source
 const int BS_COUNT = 6;
-bstr rt_part(int i); bstr compiler_part(int i); bstr server_part(int i); bstr core_part(int i);
-bstr bs_part(int k, int i) {
-	if (k == 0) return rt_part(i);
-	if (k == 1) return compiler_part(i);
-	if (k == 2) return server_part(i);
-	if (k == 3) return run.std_part(i);
-	if (k == 4) return run.icon_part(i);
-	return core_part(i);
+embed "src/runtime/rt.zc" as bstr rt_embedded;
+embed "src/compiler/compiler.zc" as bstr compiler_embedded;
+embed "src/lsp/server.zc" as bstr server_embedded;
+embed "src/core/core.zc" as bstr core_embedded;
+bstr bs_text(int k) {
+	if (k == 0) return rt_embedded;
+	if (k == 1) return compiler_embedded;
+	if (k == 2) return server_embedded;
+	if (k == 3) return run.std_source();
+	if (k == 4) return run.icon_source();
+	return core_embedded;
 }
 char* bs_uri(int k) {
 	if (k == 0) return "tinyvm:/rt.zc";
@@ -2108,21 +2120,15 @@ char* bs_uri(int k) {
 }
 // the document of built-in source k, loaded the first time it is asked for
 int bs_load(int k) {
-	int i, n = 0, j = 0, b; bstr p; word text;
+	int i, n = 0, j = 0; bstr p; word text;
 	if (!bs_idx) bs_idx = lsp_grow(0, 0, BS_COUNT);
 	if (bs_idx[k]) return bs_idx[k] - 1;
-	while (1) { p = bs_part(k, j); if (!p) break; n = n + rt.len_s(p); j++; }
-	text = lsp_grow(0, 0, (n >> 2) + 3);
-	n = 0; j = 0;
-	while (1) {
-		p = bs_part(k, j); if (!p) break;
-		b = 0;
-		while (b < rt.len_s(p)) {
-			if ((n & 3) == 0) text[n >> 2] = 0;
-			text[n >> 2] = text[n >> 2] | (rt.at_s(p, b) << ((n & 3) * 8));
-			n++; b++;
-		}
-		j++;
+	p = bs_text(k); j = rt.len_s(p);
+	text = lsp_grow(0, 0, (j >> 2) + 3);
+	while (n < j) {
+		if ((n & 3) == 0) text[n >> 2] = 0;
+		text[n >> 2] = text[n >> 2] | (rt.at_s(p, n) << ((n & 3) * 8));
+		n++;
 	}
 	i = docnew(bs_uri(k), rt.len_w(bs_uri(k)));
 	doff[i] = text; dsize[i] = n; dver[i] = 1; dgen[i]++;
@@ -2334,8 +2340,13 @@ int fm_symbol(int base, int o, int size) {
 	return n;
 }
 // split document i into tokens, each with the spaces before it on its line (-1 for the first of a line)
+// the document the token arrays describe: hover lookups lex the same documents again and
+// again, so a lex of an unchanged document is reused
+int fm_doc = 0 - 1, fm_gen, fm_size; word fm_base;
 int fm_lex(int i) {
 	int base = doff[i], size = dsize[i], o = 0, ln = 0, gap = 0 - 1, c, s, q, e, el, n;
+	if (fm_doc == i && fm_gen == dgen[i] && fm_base == base && fm_size == size && fm_s) return 0;
+	fm_doc = i; fm_gen = dgen[i]; fm_base = base; fm_size = size;
 	fm_nt = 0;
 	if (!fm_s) {
 		fm_tcap = 256;
diff --git a/src/micro/micro.c b/src/micro/micro.c
index 528382a..f598c80 100644
--- a/src/micro/micro.c
+++ b/src/micro/micro.c
@@ -30,13 +30,7 @@
 #else
 #define VM_TLS
 #endif
-#ifdef USE_LSP_GENOME
-#include "lsp_genome.h"
-#elif defined(GENOME_H)
-#include GENOME_H
-#else
 #include "genome.h"
-#endif
 #include "micro_port.h"
 #include "fops.h"
 #include "bops.h"
@@ -779,7 +773,7 @@ int micro_run(void)
 		micro_msg("zy: genome does not fit\n");
 		return 1;
 	}
-	for (i = 0; i < GLEN; i++) m[GORG + i] = genome[i];
+	for (i = 0; i < GLEN; i++) m[GORG + i] = genome_word(i);
 	jknown = 0;
 	return run(GORG);
 }
diff --git a/src/runtime/rt.zc b/src/runtime/rt.zc
index ee3594d..a54d88c 100644
--- a/src/runtime/rt.zc
+++ b/src/runtime/rt.zc
@@ -760,7 +760,10 @@ word .u new_t(int n, int t) {
 	if (dbg & 1) note_alloc(p, alloc_line);
 	return p;
 }
-// allocate n words without a type stamp; the caller owns the fresh object.
+// new(n) allocates n zeroed words without a type stamp. new(T) and new(T, n) allocate
+// a fresh heap object of type T (n of them for the second form) and stamp T in its
+// header; the compiler rewrites those forms to new_t or new_k. the caller owns it,
+// and the analyzer frees it when its owner's block ends.
 word .u new(int n) { return new_t(n, 0); }
 // the compiler works out the size class of a constant-size new at compile
 // time (k is the class of n + HDR words), so a repeated allocation of the same
@@ -1380,3 +1383,28 @@ char* .u readfile(char* path) {
 	syscall(SYS_CLOSE, fd, 0, 0);
 	return buf;
 }
+// reads a file's bytes into an owned block, one byte to a word after a length word:
+// [n, b0, b1, ...]. unlike readfile, a 0 byte in the file is kept. returns null if
+// opening fails.
+word.u readbytes(char* path) {
+	int fd; word buf; int n = 0, got, cap; word nb;
+	fd = syscall(SYS_OPEN, path, 0, 0);
+	if (fd < 0) return 0;
+	cap = 256;
+	buf = new(cap);
+	while (1) {
+		if (n + 130 >= cap) {
+			nb = new(cap + cap);
+			copy_w(nb, buf, n + 1);
+			free(buf);
+			buf = nb;
+			cap = cap + cap;
+		}
+		got = syscall(SYS_READ, fd, buf + 1 + n, 128);
+		if (got <= 0) break;
+		n = n + got;
+	}
+	buf[0] = n;
+	syscall(SYS_CLOSE, fd, 0, 0);
+	return buf;
+}
diff --git a/src/tools/automap.sh b/src/tools/automap.sh
index 69849ca..ff559ac 100755
--- a/src/tools/automap.sh
+++ b/src/tools/automap.sh
@@ -3,7 +3,8 @@
 #   src/tools/automap.sh PRESET OUTDIR FILE...
 # PRESET is run, small, default or lsp. DOCS=1 makes the genome with its doc comments. FILE... are appended after the map's own
 # rt.zc (and compiler.zc, for the presets that carry the compiler). the result
-# is OUTDIR/memmap.h and OUTDIR/genome.h, and they agree with each other.
+# is OUTDIR/memmap.h and OUTDIR/genome.bin, and they agree with each other. a core
+# compiled with -IOUTDIR --embed-dir=OUTDIR embeds that image (src/core/genome.h).
 #
 # a genome's length doesn't depend on where it lives (every address is a one
 # word literal), so two passes are enough: compile once on the preset's map
@@ -14,15 +15,14 @@
 # GENMAP can name a genmap that is already built.
 set -e
 case "${1:-}" in
-    --help|-h) printf '%s\n' 'usage: src/tools/automap.sh run|small|default|lsp OUTDIR FILE...' 'builds a genome and memory map sized to the supplied source files.' 'output: OUTDIR/genome.h and OUTDIR/memmap.h' 'environment: CC selects the c compiler; DOCS=1 retains documentation; GENMAP selects genmap.'; exit 0 ;;
+    --help|-h) printf '%s\n' 'usage: src/tools/automap.sh run|small|default|lsp OUTDIR FILE...' 'builds a genome and memory map sized to the supplied source files.' 'output: OUTDIR/genome.bin and OUTDIR/memmap.h' 'environment: CC selects the c compiler; DOCS=1 retains documentation; GENMAP selects genmap.'; exit 0 ;;
     -*) echo "automap: unknown option $1; use --help for usage" >&2; exit 2 ;;
 esac
 cd "$(dirname "$0")/../.."
 [[ $# -ge 2 ]] || { echo 'usage: src/tools/automap.sh run|small|default|lsp OUTDIR FILE...' >&2; exit 2; }
 P=$1; O=$2; shift 2
 [ -n "$P" ] && [ -n "$O" ] || { echo "usage: src/tools/automap.sh run|small|default|lsp OUTDIR FILE..." >&2; exit 2; }
-CC=${CC:-gcc}
-bash src/tools/embed.sh all --check || bash src/tools/embed.sh all
+CC=${CC:-$(sh src/tools/findcc.sh)}
 mkdir -p "$O"
 ZC0=$O/.zc0
 if [ -z "$GENMAP" ]; then
@@ -33,32 +33,36 @@ lay() {	# $1 = genome slot, or empty for the preset's own
 	rm -rf "$O/map"
 	"$GENMAP" --preset "$P" --grow ${1:+--genome $1} -o "$O/map" >/dev/null 2>&1
 	$CC -O1 -w -fwrapv src/tools/zc0.c -I"$O/map" -Isrc/core -o "$ZC0"
+	$CC -O1 -w -fwrapv src/tools/mkgenome.c -I"$O/map" -o "$O/.mkgenome"
 }
 build() {
-	if [ -f "$O/map/compiler.zc" ]; then cat "$O/map/rt.zc" src/core/core.zc "$O/map/compiler.zc" "$@"; else cat "$O/map/rt.zc" src/core/core.zc "$@"; fi | "$ZC0"
+	if [ -f "$O/map/compiler.zc" ]; then cat "$O/map/rt.zc" src/core/core.zc "$O/map/compiler.zc" "$@"; else cat "$O/map/rt.zc" src/core/core.zc "$@"; fi | "$ZC0" > "$O/image.bin"
+	"$O/.mkgenome" < "$O/image.bin" > "$O/genome.bin"
 }
 # with DOCS=1 the genome is made again with zc0 built for docs (ZC0DOCS), so the
 # image carries the doc comments of the sources and the program can answer
 # docofs(). the image is the same code either way; the docs are stored after it.
 docs() {
 	$CC -O1 -w -fwrapv -DZC0DOCS src/tools/zc0.c -I"$O/map" -Isrc/core -o "$O/.zc0docs"
-	if [ -f "$O/map/compiler.zc" ]; then cat "$O/map/rt.zc" src/core/core.zc "$O/map/compiler.zc" "$@"; else cat "$O/map/rt.zc" src/core/core.zc "$@"; fi | "$O/.zc0docs"
+	if [ -f "$O/map/compiler.zc" ]; then cat "$O/map/rt.zc" src/core/core.zc "$O/map/compiler.zc" "$@"; else cat "$O/map/rt.zc" src/core/core.zc "$@"; fi | "$O/.zc0docs" > "$O/image.bin"
+	"$O/.mkgenome" < "$O/image.bin" > "$O/genome.bin"
 }
-len() { grep -m1 '#define GLEN' "$1" | awk '{print $3}'; }
+len() { echo $(( $(wc -c < "$1") / 8 )); }
 lay ""
-build "$@" > "$O/genome.h"
-glen=$(len "$O/genome.h")
+build "$@"
+glen=$(len "$O/genome.bin")
 slot=$(( (glen + 4095) / 4096 * 4096 ))
 lay "$slot"
-build "$@" > "$O/genome.h"
+build "$@"
 if [ -n "$DOCS" ]; then
 	lay $((slot + 65536))		# room for the image with its docs while it is being made
-	docs "$@" > "$O/genome.h"
-	glen=$(len "$O/genome.h")
+	docs "$@"
+	glen=$(len "$O/genome.bin")
 	slot=$(( (glen + 4095) / 4096 * 4096 ))
 	lay "$slot"
-	docs "$@" > "$O/genome.h"
+	docs "$@"
 fi
-[ "$(len "$O/genome.h")" = "$glen" ] || { echo "automap: the genome changed length with the map" >&2; exit 1; }
+rm -f "$O/image.bin"
+[ "$(len "$O/genome.bin")" = "$glen" ] || { echo "automap: the genome changed length with the map" >&2; exit 1; }
 cp "$O/map/memmap.h" "$O/map/map.txt" "$O/"
 echo "automap $P: genome $glen words in a slot of $slot, $(grep -m1 '^MW' "$O/map/map.txt")"
diff --git a/src/tools/bootstrap-check.sh b/src/tools/bootstrap-check.sh
index a5de341..7acd74c 100755
--- a/src/tools/bootstrap-check.sh
+++ b/src/tools/bootstrap-check.sh
@@ -2,19 +2,23 @@
 # rebuild the bootstrap one stage and report what the compiler says about itself.
 # zc0 (stage 0) compiles rt+core+compiler into build/s0, s0 becomes zy0, and zy0
 # runs build.zc over the same sources to produce the image. ownership diagnostics
-# come back in the image, so print them instead of the word dump.
+# come back in place of the image; mkgenome rejects them and prints them.
 set -e
+case "${1:-}" in
+    --help|-h) printf '%s\n' 'usage: src/tools/bootstrap-check.sh' 'runs the first two bootstrap stages and prints the compiler diagnostics on its own source, or the image size.'; exit 0 ;;
+    -*) echo "bootstrap-check: unknown option $1; use --help for usage" >&2; exit 2 ;;
+esac
 cd "$(dirname "$0")/../.."
-mkdir -p bin build/s0 build/s1 build/core
-cc -O1 -w -fwrapv src/tools/zc0.c -Isrc/core -o bin/zc0
-cc -O1 -w -fwrapv src/tools/mkgenome.c -Isrc/core -o bin/mkgenome
-cp src/core/core.c src/core/io_linux.c src/core/memmap.h src/core/fops.h src/core/bops.h src/core/stack.h build/s0/
-cat src/runtime/rt.zc src/core/core.zc src/compiler/compiler.zc | bin/zc0 > build/s0/genome.h
-cc -O2 -w -fwrapv -pthread -DJTYPE=int build/s0/core.c build/s0/io_linux.c -o build/zy0
-(cat src/tools/build.zc; printf '`'; cat src/runtime/rt.zc src/core/core.zc src/compiler/compiler.zc) | build/zy0 > build/g1.bin
-if ! grep -q '^zc: ' build/g1.bin 2>/dev/null; then
-    echo "image ok: $(wc -c < build/g1.bin) bytes"
+make -s build/bin/zc0 build/bin/mkgenome
+CC=${CC:-$(sh src/tools/findcc.sh)}
+SRC="src/runtime/rt.zc src/core/core.zc src/compiler/compiler.zc"
+mkdir -p build/s0 build/s1
+cat $SRC | build/bin/zc0 > build/s0/g0.bin
+build/bin/mkgenome < build/s0/g0.bin > build/s0/genome.bin
+$CC -O2 -w -fwrapv -pthread -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core/map --embed-dir=build/s0 -o build/s0/zy0
+(cat src/tools/build.zc; printf '`'; cat $SRC) | build/s0/zy0 > build/s1/g1.bin
+if build/bin/mkgenome < build/s1/g1.bin > build/s1/check.bin; then
+    echo "image ok: $(wc -c < build/s1/g1.bin) bytes"
 else
-    echo "--- compiler diagnostics on its own source ---"
-    cat -v build/g1.bin
-fi
\ No newline at end of file
+    exit 1
+fi
diff --git a/src/tools/embed.sh b/src/tools/embed.sh
deleted file mode 100755
index 59a377f..0000000
--- a/src/tools/embed.sh
+++ /dev/null
@@ -1,89 +0,0 @@
-#!/bin/bash
-# embeds source text in the compiler, so the editor can show a built-in's definition and `include std;` needs
-# no file. a text becomes a function that returns it in pieces of at most 3000 bytes (the bootstrap
-# compiler's token buffer is 4 KB), one byte string per piece:
-#   bstr NAME_part(int i) { if (i == 0) return b"..."; if (i == 1) return b"..."; ... return 0; }
-#
-#   src/tools/embed.sh all            embeds src/lib modules in the compiler
-#   src/tools/embed.sh all --check    exits 1 when an embedded module is out of date
-#   src/tools/embed.sh lsp OUT        writes OUT: rt_part, compiler_part and server_part, for the language server's image
-set -e
-case "${1:-}" in
-    --help|-h) printf '%s\n' 'usage: src/tools/embed.sh std|icon|all [--check]' '       src/tools/embed.sh lsp OUT' 'embeds library sources in the compiler, or writes the lsp source providers to OUT.' 'options:' '  --check     report stale embedded library sources without changing files' '  --help, -h  show this help and exit'; exit 0 ;;
-    -*) echo "embed: unknown option $1; use --help for usage" >&2; exit 2 ;;
-esac
-cd "$(dirname "$0")/../.."
-export LC_ALL=C
-# parts NAME FILE: the NAME_part function for FILE
-parts() {
-	echo "bstr $1_part(int i) {"
-	awk -v LIMIT=3000 '
-	function flush() { if (cnt > 0) { printf("\tif (i == %d) return b\"%s\";\n", n, buf); n++; buf = ""; cnt = 0 } }
-	{
-		line = $0; sub(/\r$/, "", line); line = line "\n"
-		len = length(line)
-		for (j = 1; j <= len; j++) {
-			if (cnt >= LIMIT) flush()
-			c = substr(line, j, 1)
-			if (c == "\\") e = "\\\\"; else if (c == "\"") e = "\\\""; else if (c == "\t") e = "\\t"; else if (c == "\n") e = "\\n"; else e = c
-			buf = buf e; cnt++
-		}
-	}
-	END { flush() }' "$2"
-	echo "	return 0;"
-	echo "}"
-}
-embed() {
-	name=$1; file=$2; check=$3; C=src/compiler/compiler.zc; T=$(mktemp -d)
-	BEGIN_MARK="// ---- embedded $name library (generated by src/tools/embed.sh from $file; do not edit) ----"
-	END_MARK="// ---- end embedded $name library ----"
-	if grep -qF "$BEGIN_MARK" "$C"; then
-		awk -v b="$BEGIN_MARK" '$0 == b { exit } { print }' "$C" > "$T/head"
-		awk -v e="$END_MARK" 'found { print } $0 == e { found = 1; next }' "$C" > "$T/tail"
-	else
-		cp "$C" "$T/head"
-		: > "$T/tail"
-	fi
-	{
-		cat "$T/head"
-		echo "$BEGIN_MARK"
-		parts "$name" "$file"
-		echo "$END_MARK"
-		cat "$T/tail"
-	} > "$T/new"
-	if [ "$check" = "--check" ]; then
-		cmp -s "$T/new" "$C" && result=0 || result=1
-		rm -rf "$T"
-		return "$result"
-	fi
-	cp "$T/new" "$C"
-	rm -rf "$T"
-}
-case "$1" in
-std)
-	embed std src/lib/std.zc "$2"
-	;;
-icon)
-	embed icon src/lib/icon.zc "$2"
-	;;
-all)
-	if [ "$2" = "--check" ]; then
-		embed std src/lib/std.zc --check && embed icon src/lib/icon.zc --check
-	else
-		embed std src/lib/std.zc
-		embed icon src/lib/icon.zc
-	fi
-	;;
-lsp)
-	[ -n "$2" ] || { echo "usage: src/tools/embed.sh lsp OUT" >&2; exit 2; }
-	{
-		echo "// the sources of this image, embedded (generated by src/tools/embed.sh; do not edit)"
-		parts rt src/runtime/rt.zc
-		parts compiler src/compiler/compiler.zc
-		parts server src/lsp/server.zc
-		parts core src/core/core.zc
-	} > "$2"
-	;;
-*)
-		echo "usage: src/tools/embed.sh all [--check] | std | icon | lsp OUT" >&2; exit 2;;
-esac
diff --git a/src/tools/findcc.sh b/src/tools/findcc.sh
new file mode 100755
index 0000000..caa3af3
--- /dev/null
+++ b/src/tools/findcc.sh
@@ -0,0 +1,33 @@
+#!/bin/sh
+# prints the first c compiler that accepts c23 #embed, which every core needs to
+# take in its genome (src/core/genome.h). clang 19 and gcc 15 are the first
+# releases with it, and both find #embed files through --embed-dir. a CC
+# already in the environment is tried first.
+#   src/tools/findcc.sh           a native compiler
+#   src/tools/findcc.sh --wasm    a clang that also targets wasm32
+# exits 1, naming what was tried, when nothing fits.
+case "${1:-}" in
+    --help|-h) printf '%s\n' 'usage: src/tools/findcc.sh [--wasm]' 'prints a c compiler that supports #embed; --wasm also requires the wasm32 target.' 'environment: CC is tried first.'; exit 0 ;;
+    --wasm|'') ;;
+    *) echo "findcc: unknown option $1; use --help for usage" >&2; exit 2 ;;
+esac
+wasm=${1:-}
+dir=$(mktemp -d "${TMPDIR:-/tmp}/findcc.XXXXXX") || exit 1
+trap 'rm -rf "$dir"' EXIT
+mkdir "$dir/data"
+printf 'ab' > "$dir/data/probe.bin"
+printf 'static const unsigned char probe[] = {\n#embed "probe.bin"\n};\nint main(void) { return sizeof probe == 2 ? 0 : 1; }\n' > "$dir/probe.c"
+tried=""
+for cc in ${CC:-} cc clang gcc clang-22 clang-21 clang-20 clang-19 gcc-16 gcc-15 /opt/homebrew/opt/llvm/bin/clang /usr/local/opt/llvm/bin/clang; do
+    command -v "$cc" >/dev/null 2>&1 || continue
+    tried="$tried $cc"
+    if [ -n "$wasm" ]; then
+        "$cc" --target=wasm32 -nostdlib -w --embed-dir="$dir/data" -c "$dir/probe.c" -o "$dir/probe.o" >/dev/null 2>&1 || continue
+    else
+        "$cc" -w --embed-dir="$dir/data" "$dir/probe.c" -o "$dir/probe" >/dev/null 2>&1 || continue
+    fi
+    echo "$cc"
+    exit 0
+done
+echo "findcc: no c compiler with #embed${wasm:+ and wasm32} (tried:${tried:- nothing}); install clang 19 or gcc 15, or set CC" >&2
+exit 1
diff --git a/src/tools/genmap.c b/src/tools/genmap.c
index 8a258e1..d063d36 100644
--- a/src/tools/genmap.c
+++ b/src/tools/genmap.c
@@ -609,9 +609,11 @@ static void expect_hex(const char *text, const char *where, const char *name, in
 static void check_sources(const Map *m)
 {
 	char lfa_old[64];
+	/* a memmap.h in the working directory is compared too, when there is one: the
+	   default map's header is generated into build/core and never kept in the tree */
 	FILE *mf = fopen("memmap.h", "rb");
-	const char *mm_path = mf ? (fclose(mf), "memmap.h") : "src/core/memmap.h";
-	char *rt = slurp("src/runtime/rt.zc"), *cc = slurp("src/compiler/compiler.zc"), *mm = slurp(mm_path);
+	const char *mm_path = mf ? (fclose(mf), "memmap.h") : 0;
+	char *rt = slurp("src/runtime/rt.zc"), *cc = slurp("src/compiler/compiler.zc"), *mm = mm_path ? slurp(mm_path) : 0;
 	char *rtb = between(rt, "// @map-rt", "// @end-map");
 	char *ccb = between(cc, "// @map-cc", "// @end-map");
 	static const char *rt_names[] = {
@@ -644,7 +646,7 @@ static void check_sources(const Map *m)
 	if (!strstr(rt, lfa_old)) die("src/runtime/rt.zc no longer has the default lfa immediate");
 	if (!strstr(cc, "ZFP - 16384")) die("src/compiler/compiler.zc lost its initial type-area formula");
 	for (i = 0; rt_names[i]; i++) expect_hex(rtb, "src/runtime/rt.zc", rt_names[i], rt_vals[i]);
-	for (i = 0; rt_names[i]; i++) {
+	for (i = 0; mm && rt_names[i]; i++) {
 		if (!strcmp(rt_names[i], "MAGIC") || !strcmp(rt_names[i], "HEAP_GROW")) continue;
 		expect_hex(mm, mm_path, !strcmp(rt_names[i], "MW") ? "PW" : rt_names[i], rt_vals[i]);
 	}
@@ -700,7 +702,7 @@ static void usage_status(int status)
 		"--preset default has a growing heap above the stacks; fixed is the old 1,081,344-word map.\n"
 		"--grow lets a map with a fixed size get bigger when its genome needs more room.\n"
 		"--mode packs a compiler or a run-only image; spare words go to the data stack.\n"
-		"--check compares that layout to memmap.h and the checked-in const blocks.\n");
+		"--check compares that layout to the checked-in const blocks (and to ./memmap.h if present).\n");
 	exit(status);
 }
 
diff --git a/src/tools/mkgenome.c b/src/tools/mkgenome.c
index 3bf1533..9720760 100644
--- a/src/tools/mkgenome.c
+++ b/src/tools/mkgenome.c
@@ -1,7 +1,12 @@
-/* turns a genome image (little-endian 64-bit words on stdin, as written by
-   src/tools/build.zc) into genome.h */
+/* checks a genome image (little-endian 64-bit words on stdin, as written by
+   zc0 or src/tools/build.zc) against the memory map it was built with, and
+   copies it to stdout unchanged. the cores #embed the result (src/core/genome.h),
+   so this is the gate that keeps a compiler's diagnostics out of a core: when
+   the input is not an image for this map, nothing is written and the input is
+   shown on stderr, since it is usually the compiler's error report. */
 #include <stdio.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
 #ifdef _WIN32
 #include <fcntl.h>
@@ -11,8 +16,9 @@
 int main(int argc, char **argv)
 {
 	if (argc == 2 && (!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h"))) {
-		fputs("usage: mkgenome [--help|-h] < image.bin > genome.h\n"
-		      "converts little-endian 64-bit image words into a c genome header.\n"
+		fputs("usage: mkgenome [--help|-h] < image.bin > genome.bin\n"
+		      "checks little-endian 64-bit image words against this memory map and copies them\n"
+		      "to stdout. input that is not an image is reported on stderr and nothing is written.\n"
 		      "the image must match the memory layout selected when mkgenome is built.\n"
 		      "options:\n  --help, -h  show this help and exit\n", stdout);
 		return 0;
@@ -22,19 +28,29 @@ int main(int argc, char **argv)
 	_setmode(_fileno(stdin), _O_BINARY);
 	_setmode(_fileno(stdout), _O_BINARY);
 #endif
-	unsigned char b[8]; int n = 0; size_t got;
-	printf("#define GORG %d\nstatic const int64_t genome[] = {", GORG);
-	while ((got = fread(b, 1, 8, stdin)) == 8) {
-		uint64_t u = (uint64_t)b[0] | (uint64_t)b[1] << 8 | (uint64_t)b[2] << 16 | (uint64_t)b[3] << 24
-			| (uint64_t)b[4] << 32 | (uint64_t)b[5] << 40 | (uint64_t)b[6] << 48 | (uint64_t)b[7] << 56;
-		if ((n == 0 && u != (uint64_t)FTOP * 2 + 1) ||
-		    (n == 1 && u != (uint64_t)ZFP * 2 + 1) || (n == 2 && u != 4)) {
-			fprintf(stderr, "mkgenome: input is not a genome for this map\n"); return 1;
+	size_t n = 0, cap = 1 << 20, got;
+	unsigned char *b = malloc(cap);
+	if (!b) { fputs("mkgenome: out of memory\n", stderr); return 1; }
+	while ((got = fread(b + n, 1, cap - n, stdin)) > 0) {
+		n += got;
+		if (n == cap) {
+			unsigned char *next = cap > ((size_t)1 << 30) ? 0 : realloc(b, cap * 2);
+			if (!next) { fputs("mkgenome: image too large\n", stderr); return 1; }
+			b = next; cap *= 2;
 		}
-		printf("%s%lld", !n ? "\n" : n % 12 ? "," : ",\n", (long long)u);
-		n++;
 	}
-	if (got || ferror(stdin) || n < 7) { fprintf(stderr, "mkgenome: incomplete genome\n"); return 1; }
-	printf("\n};\n#define GLEN %d\n", n);
-	return n ? 0 : 1;
+	if (ferror(stdin)) { fputs("mkgenome: read failed\n", stderr); return 1; }
+	int ok = n >= 8 * 7 && n % 8 == 0;
+	for (int i = 0; ok && i < 3; i++) {
+		uint64_t u = 0;
+		for (int k = 0; k < 8; k++) u |= (uint64_t)b[i * 8 + k] << (k * 8);
+		if (u != (i == 0 ? (uint64_t)FTOP * 2 + 1 : i == 1 ? (uint64_t)ZFP * 2 + 1 : 4)) ok = 0;
+	}
+	if (!ok) {
+		if (n >= 4 && !memcmp(b, "zc: ", 4)) fwrite(b, 1, n, stderr);
+		fprintf(stderr, n % 8 || n < 8 * 7 ? "mkgenome: incomplete genome\n" : "mkgenome: input is not a genome for this map\n");
+		return 1;
+	}
+	if (fwrite(b, 1, n, stdout) != n || fflush(stdout)) { fputs("mkgenome: write failed\n", stderr); return 1; }
+	return 0;
 }
diff --git a/src/tools/mklsp.sh b/src/tools/mklsp.sh
index 9bab550..1c44998 100755
--- a/src/tools/mklsp.sh
+++ b/src/tools/mklsp.sh
@@ -2,21 +2,19 @@
 # builds the language server: src/tools/mklsp.sh [outdir] leaves outdir/zclsp.
 # the server is the real compiler (src/compiler/compiler.zc) in check mode plus
 # src/lsp/server.zc. its memory map is sized to that program by src/tools/automap.sh,
-# so the genome slot is as big as it needs to be and no bigger.
+# so the genome slot is as big as it needs to be and no bigger. the image carries
+# the doc comments (DOCS=1) and, through embed declarations in server.zc, its own
+# sources, so hover and go to definition work on built-ins. the core takes the
+# image in with #embed as lsp_genome.bin.
 set -e
 case "${1:-}" in
-    --help|-h) printf '%s\n' 'usage: src/tools/mklsp.sh [OUTDIR]' 'builds the native language server in OUTDIR/zclsp; defaults to build/lsp.' 'environment: CC selects the c compiler.'; exit 0 ;;
+    --help|-h) printf '%s\n' 'usage: src/tools/mklsp.sh [OUTDIR]' 'builds the native language server in OUTDIR/zclsp; defaults to build/lsp.' 'environment: CC selects the c compiler (one with #embed).'; exit 0 ;;
     -*) echo "mklsp: unknown option $1; use --help for usage" >&2; exit 2 ;;
 esac
 cd "$(dirname "$0")/../.."
-O=${1:-build/lsp}; CC=${CC:-gcc}
-# DOCS=1: the image carries the doc comments, so hover can show what a name is for
+O=${1:-build/lsp}; CC=${CC:-$(sh src/tools/findcc.sh)}
+export CC
 mkdir -p "$O"
-bash src/tools/embed.sh all --check || bash src/tools/embed.sh all
-# the image carries its own sources (for go to definition into a built-in)
-bash src/tools/embed.sh lsp "$O/embed.zc"
-DOCS=1 bash src/tools/automap.sh lsp "$O" src/lsp/server.zc "$O/embed.zc" >/dev/null
-rm -rf "$O/src"; mkdir -p "$O/src"
-cp src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h "$O/memmap.h" "$O/src/"
-cp "$O/genome.h" "$O/src/lsp_genome.h"
-$CC -O2 -w -fwrapv -pthread -DJTYPE=int -DZY_SANDBOX -DUSE_LSP_GENOME "$O/src/core.c" "$O/src/io_linux.c" -I"$O/src" -o "$O/zclsp"
+DOCS=1 bash src/tools/automap.sh lsp "$O" src/lsp/server.zc >/dev/null
+cp "$O/genome.bin" "$O/lsp_genome.bin"
+$CC -O2 -w -fwrapv -pthread -DJTYPE=int -DZY_SANDBOX -DUSE_LSP_GENOME src/core/core.c src/core/io_linux.c -Isrc/core -I"$O" --embed-dir="$O" -o "$O/zclsp"
diff --git a/src/tools/mklspwasm.sh b/src/tools/mklspwasm.sh
index 4789eab..d05a5a7 100755
--- a/src/tools/mklspwasm.sh
+++ b/src/tools/mklspwasm.sh
@@ -3,21 +3,22 @@
 # by default, or the path given as the first argument. the server is the compiler
 # and src/lsp/server.zc on the map and genome that src/tools/mklsp.sh made in build/lsp,
 # and the microcore (src/micro/micro.c) runs them. the host is client/wasmproc.js.
-# needs clang with the wasm32 target and wasm-ld; run src/tools/mklsp.sh first.
+# needs clang with the wasm32 target, #embed and wasm-ld; run src/tools/mklsp.sh first.
 #   src/tools/mklspwasm.sh [outfile.wasm]
 set -e
 case "${1:-}" in
-    --help|-h) printf '%s\n' 'usage: src/tools/mklspwasm.sh [OUTFILE.wasm]' 'builds the wasm language server; defaults to build/editors/vscode/server/lsp.wasm.' 'requires clang with wasm32 support and wasm-ld.' 'environment: LSP_BUILD_DIR selects the native lsp build; LSP_REUSE_BUILD=1 reuses its image.'; exit 0 ;;
+    --help|-h) printf '%s\n' 'usage: src/tools/mklspwasm.sh [OUTFILE.wasm]' 'builds the wasm language server; defaults to build/editors/vscode/server/lsp.wasm.' 'requires clang with wasm32 and #embed support, and wasm-ld.' 'environment: WASM_CC selects the compiler; LSP_BUILD_DIR selects the native lsp build; LSP_REUSE_BUILD=1 reuses its image.'; exit 0 ;;
     -*) echo "mklspwasm: unknown option $1; use --help for usage" >&2; exit 2 ;;
 esac
 cd "$(dirname "$0")/../.."
 OUT=${1:-build/editors/vscode/server/lsp.wasm}
 LSP_BUILD_DIR=${LSP_BUILD_DIR:-build/lsp}
+WASM_CC=${WASM_CC:-$(sh src/tools/findcc.sh --wasm)}
 if [ "${LSP_REUSE_BUILD:-0}" != 1 ]; then bash src/tools/mklsp.sh "$LSP_BUILD_DIR" >/dev/null; fi
-[ -f "$LSP_BUILD_DIR/src/lsp_genome.h" ] || { echo "mklspwasm: no language server image in $LSP_BUILD_DIR" >&2; exit 1; }
+[ -f "$LSP_BUILD_DIR/lsp_genome.bin" ] || { echo "mklspwasm: no language server image in $LSP_BUILD_DIR" >&2; exit 1; }
 mkdir -p "$(dirname "$OUT")"
-clang --target=wasm32 -O2 -w -fwrapv -nostdlib -fno-builtin -mbulk-memory -DJTYPE=int -DUSE_LSP_GENOME \
-	-I"$LSP_BUILD_DIR/src" -Isrc/micro src/micro/micro.c src/micro/port_wasm_stream.c \
+"$WASM_CC" --target=wasm32 -O2 -w -fwrapv -nostdlib -fno-builtin -mbulk-memory -DJTYPE=int -DUSE_LSP_GENOME \
+	-Isrc/core -I"$LSP_BUILD_DIR" --embed-dir="$LSP_BUILD_DIR" -Isrc/micro src/micro/micro.c src/micro/port_wasm_stream.c \
 	-Wl,--no-entry -Wl,--export=wasm_chunk -Wl,--export=wasm_chunk_cap -Wl,--export=wasm_feed \
 	-Wl,--export=wasm_polling -Wl,--export=wasm_close -Wl,--export=wasm_start -Wl,--export=wasm_resume \
 	-Wl,--export=memory -Wl,--allow-undefined -Wl,--initial-memory=41943040 -Wl,-z,stack-size=65536 \
diff --git a/src/tools/mkvsix.sh b/src/tools/mkvsix.sh
index df9e703..61fe9a8 100755
--- a/src/tools/mkvsix.sh
+++ b/src/tools/mkvsix.sh
@@ -1,13 +1,12 @@
 #!/bin/bash
 # builds the vs code extension, with the language server inside it: the tinyvm
 # javascript vm (built from src/js/tinyvm.ts) and the server's image
-# (build/js/lsp.json, from build/lsp/genome.h and its map), and the wasm server
+# (build/js/lsp.bin and its map in lsp.json, from build/lsp), and the wasm server
 # (src/tools/mklspwasm.sh) when clang can build it. needs node and tsc; the
 # server build (src/tools/mklsp.sh) runs first if build/lsp is missing.
 #
-# everything generated lands in build/. the packaged files are staged into
-# editors/vscode/server/ only for as long as vsce is packing, then removed, so a
-# fresh clone has no extension until it is built.
+# everything generated lands in build/: the server files in
+# build/editors/vscode/server, the packing copy of the extension in build/vsix.
 #   src/tools/mkvsix.sh [outfile.vsix]
 set -e
 case "${1:-}" in
@@ -20,31 +19,33 @@ case "$OUT" in /*) ;; *) OUT="$PWD/$OUT" ;; esac
 mkdir -p "$(dirname "$OUT")"
 JS=build/js
 STAGE=build/editors/vscode/server
-PACKDIR=editors/vscode/server
 
 bash src/tools/mklsp.sh build/lsp >/dev/null
 # typescript errors stop packaging, so broken generated code is never shipped.
 command -v tsc >/dev/null || { echo "mkvsix: tsc is not installed" >&2; exit 1; }
+make --no-print-directory build/js/layout.js >/dev/null
 tsc src/js/tinyvm.ts --target es2020 --lib es2020,dom --module commonjs --outDir "$JS"
 node src/js/extract_lsp.js
 mkdir -p "$STAGE"
-cp "$JS/tinyvm.js" "$JS/layout.js" "$JS/lsp.json" "$STAGE/"
+cp "$JS/tinyvm.js" "$JS/layout.js" "$JS/lsp.json" "$JS/lsp.bin" "$STAGE/"
 # the wasm server runs when there is one; without clang the vm server is packed alone
-if command -v clang >/dev/null && clang --print-targets | grep -q wasm32; then
+if sh src/tools/findcc.sh --wasm >/dev/null 2>&1; then
     LSP_BUILD_DIR=build/lsp LSP_REUSE_BUILD=1 bash src/tools/mklspwasm.sh "$STAGE/lsp.wasm"
 else
     rm -f "$STAGE/lsp.wasm"
-    echo "no clang with wasm32: packing the javascript vm server only" >&2
+    echo "no clang with wasm32 and #embed: packing the javascript vm server only" >&2
 fi
 
-# vsce packs the extension directory, so the server has to sit inside it while
-# it runs. stage it, package, and leave the tree as it was.
-cleanup() { rm -rf "$PACKDIR"; }
-trap cleanup EXIT INT TERM
-rm -rf "$PACKDIR"
-mkdir -p "$PACKDIR"
-cp "$STAGE"/* "$PACKDIR"/
-cd editors/vscode
+# vsce packs a whole extension directory, so the extension is copied into
+# build/vsix/extension with the server beside its client, and packed there. the
+# tree is never written to.
+PACKROOT=build/vsix/extension
+rm -rf "$PACKROOT"
+mkdir -p "$PACKROOT"
+cp -R editors/vscode/. "$PACKROOT/"
+mkdir -p "$PACKROOT/server"
+cp "$STAGE"/* "$PACKROOT/server/"
+cd "$PACKROOT"
 if [ -n "${VSCE:-}" ]; then
     "$VSCE" package --allow-missing-repository --skip-license -o "$OUT" >/dev/null
 elif command -v vsce >/dev/null; then
@@ -52,4 +53,4 @@ elif command -v vsce >/dev/null; then
 else
     npx -y @vscode/vsce package --allow-missing-repository --skip-license -o "$OUT" >/dev/null
 fi
-echo "$OUT"
\ No newline at end of file
+echo "$OUT"
diff --git a/src/tools/zc0.c b/src/tools/zc0.c
index 446557b..5f5b97d 100644
--- a/src/tools/zc0.c
+++ b/src/tools/zc0.c
@@ -1,7 +1,8 @@
 /* zc0: stage 0 of the bootstrap. a small c compiler for the subset of zc that
    compiler.zc is written in. it reads zc source on stdin and writes a genome
-   header (vm words placed at GORG) on stdout, in the same image layout the
-   resident compiler's image mode produces. no lifetime analysis, no quote, no
+   image (vm words placed at GORG, as little-endian 64-bit words) on stdout, in
+   the same image layout the resident compiler's image mode produces. the cores
+   embed that file with #embed (src/core/genome.h). no lifetime analysis, no quote, no
    parse words, no block expressions: those only exist in compiler.zc. tags
    (m, d, -> u) and casts (as u, as d) are parsed and recorded in signatures
    but not checked. */
@@ -454,12 +455,13 @@ static void strlit(void)	/* inline word string: jump over it, push its address *
 static void bstrlit(void)
 {
 	int j = here, a, i = 0, k, n = (int)strlen(ts);
+	const char *b = ts;
 	uint64_t w;
 	lit(0); op(O_JMP); a = here;
 	emit(n);
 	while (i < n) {
 		w = 0; k = 0;
-		while (k < 8 && i < n) { w |= (uint64_t)(unsigned char)ts[i] << (k * 8); k++; i++; }
+		while (k < 8 && i < n) { w |= (uint64_t)(unsigned char)b[i] << (k * 8); k++; i++; }
 		emit((int64_t)w);
 	}
 	if ((n & 7) == 0) emit(0);
@@ -497,7 +499,7 @@ static void primary(void)
 			else if (((s->sig >> 4) & 15) != 1) die("multiple enhancement outputs need asm");
 			xs = 0; xf = 0; return;
 		}
-		if (!strcmp(n, "put_s") && na == 1 && xs) fnref("put_bs");
+		if ((!strcmp(n, "put_s") || !strcmp(n, "rt.put_s")) && na == 1 && xs) fnref(n[0] == 'r' ? "rt.put_bs" : "put_bs");
 		else if (!strcmp(n, "len")) fnref("len_s");
 		else fnref(n);
 		op(O_CALL);
@@ -794,6 +796,77 @@ static void enhdef(void)
 	s = add(n, K_ENH, nenh++); s->sig = np + nout * 16 + d * 256;
 	expect(";");
 }
+/* embed "path" as [type] name; at the top level: a global holding the file's bytes,
+   read when the image is built. the path is relative to the working directory.
+   bstr (the default) packs the bytes; char* keeps one character to a word; a
+   number takes them little-endian; T[] and T[n] lay them out as the array's
+   elements. the same rules as the resident compiler's kw_embed. */
+static int embed_width(const char *t, int star)
+{
+	if (star) return 0;
+	if (!strcmp(t, "char") || !strcmp(t, "u8") || !strcmp(t, "i8") || !strcmp(t, "byte")) return 1;
+	if (!strcmp(t, "u16") || !strcmp(t, "i16")) return 2;
+	if (!strcmp(t, "u32") || !strcmp(t, "i32") || !strcmp(t, "f32")) return 4;
+	if (!strcmp(t, "int") || !strcmp(t, "word") || !strcmp(t, "bool") || !strcmp(t, "float") || !strcmp(t, "f64")) return 8;
+	return 0;
+}
+static void embeddecl(void)
+{
+	char path[1024], ty[64] = "", *n; int star = 0, arr = -2, w, i, a; long len; unsigned char *buf; FILE *f;
+	if (tk != T_STR) die("embed takes a path in quotes: embed \"file\" as name;");
+	snprintf(path, sizeof path, "%s", ts); next();
+	expect("as");
+	if (tk == T_ID) {
+		Lex L; lexsave(&L); next();
+		int named = is(";"); lexrest(&L);
+		if (!named) {
+			snprintf(ty, sizeof ty, "%s", ts); next();
+			while (accept("*")) star++;
+			if (accept("[")) { arr = -1; if (tk == T_NUM) { arr = (int)tv; next(); } expect("]"); }
+		}
+	}
+	n = ident(); expect(";");
+	if (!(f = fopen(path, "rb"))) die("can't read the file named by embed");
+	fseek(f, 0, SEEK_END); len = ftell(f); fseek(f, 0, SEEK_SET);
+	buf = malloc((size_t)len + 1);
+	if (!buf || fread(buf, 1, (size_t)len, f) != (size_t)len) die("can't read the file named by embed");
+	fclose(f);
+	if (arr == -2 && (!ty[0] || (!strcmp(ty, "bstr") && !star))) {
+		a = here; add(n, K_GVAR, a); emit(0); img[a - GORG] = here; emit(len);
+		for (i = 0; i < len; i += 8) { uint64_t u = 0; for (w = 0; w < 8 && i + w < len; w++) u |= (uint64_t)buf[i + w] << (w * 8); emit((int64_t)u); }
+		if (!(len & 7)) emit(0);
+	} else if (arr == -2 && !strcmp(ty, "char") && star == 1) {
+		a = here; add(n, K_GVAR, a); emit(0); img[a - GORG] = here;
+		for (i = 0; i < len; i++) emit(buf[i]);
+		emit(0);
+	} else if (arr == -2) {
+		uint64_t u = 0; w = embed_width(ty, star);
+		if (!w) die("embed declares a bstr, a char*, a number or an array of numbers");
+		if (len > w) die("the embedded file is larger than the type it is declared as");
+		if (!strcmp(ty, "f32") && len != 4) die("an embedded f32 takes exactly 4 bytes");
+		if ((!strcmp(ty, "float") || !strcmp(ty, "f64")) && len != 8) die("an embedded float takes exactly 8 bytes");
+		for (i = 0; i < len; i++) u |= (uint64_t)buf[i] << (i * 8);
+		if (ty[0] == 'i' && w < 8 && (u >> (w * 8 - 1) & 1)) u |= ~(uint64_t)0 << (w * 8);
+		if (!strcmp(ty, "f32")) u = fop_s2f(u);
+		a = here; add(n, K_GVAR, a); emit((int64_t)u);
+	} else {
+		int count; w = embed_width(ty, star);
+		if (!w) die("embed declares a bstr, a char*, a number or an array of numbers");
+		if (len % w) die("the embedded file's size is not a whole number of elements");
+		count = (int)(len / w);
+		if (arr >= 0 && count > arr) die("the embedded file is larger than the array it is declared as");
+		if (arr >= 0) count = arr;
+		a = here;
+		if (!strcmp(ty, "char")) { for (i = 0; i < count; i++) emit(i < len ? buf[i] : 0); }
+		else {
+			long bytes = (long)count * w;
+			for (i = 0; i < bytes; i += 8) { uint64_t u = 0; for (int k = 0; k < 8 && i + k < bytes; k++) u |= (uint64_t)(i + k < len ? buf[i + k] : 0) << (k * 8); emit((int64_t)u); }
+			if (!bytes) emit(0);
+		}
+		add(n, K_GARR, a);
+	}
+	free(buf);
+}
 static void top1(void)
 {
     if (accept("namespace")) {
@@ -802,6 +875,7 @@ static void top1(void)
         expect(";"); return;
     }
     if (accept("include")) { do { ident(); } while (accept(",")); expect(";"); return; }
+	if (accept("embed")) { embeddecl(); return; }
 	{
 		if (accept("unchecked")) { top1(); return; }
 		if (accept("fn")) { fndef(0); return; }
@@ -898,8 +972,9 @@ static void top(void)
 int main(int argc, char **argv)
 {
 	if (argc == 2 && (!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h"))) {
-		fputs("usage: zc0 [--help|-h] < source.zc > genome.h\n"
-		      "compiles bootstrap source from stdin into a c genome header on stdout.\n"
+		fputs("usage: zc0 [--help|-h] < source.zc > genome.bin\n"
+		      "compiles bootstrap source from stdin into a genome image on stdout:\n"
+		      "little-endian 64-bit words, the format the cores #embed.\n"
 		      "source must define start(); memory layout is selected when zc0 is built.\n"
 		      "options:\n  --help, -h  show this help and exit\n", stdout);
 		return 0;
@@ -942,8 +1017,10 @@ int main(int argc, char **argv)
 	}
 	emit(0);
 	img[6] = here;
-	printf("#define GORG %d\n#define GLEN %d\nstatic const int64_t genome[] = {", GORG, here - GORG);
-	for (i = 0; i < here - GORG; i++) printf("%s%lld", !i ? "\n" : i % 12 ? "," : ",\n", (long long)img[i]);
-	printf("\n};\n");
-	return 0;
+	for (i = 0; i < here - GORG; i++) {
+		unsigned char b[8]; uint64_t u = (uint64_t)img[i];
+		for (j = 0; j < 8; j++) b[j] = (unsigned char)(u >> (j * 8));
+		if (fwrite(b, 1, 8, stdout) != 8) { fprintf(stderr, "zc0: write failed\n"); return 1; }
+	}
+	return fflush(stdout) ? 1 : 0;
 }
diff --git a/src/tools/zcc b/src/tools/zcc
index 3fb8f0c..ba38e97 100755
--- a/src/tools/zcc
+++ b/src/tools/zcc
@@ -8,7 +8,7 @@
 #
 # -o OUT    the binary to write (default: FILE without .zc)
 # -k        keep the build directory and print where it is
-# CC        the C compiler (default cc). CFLAGS adds to the default -O2
+# CC        the C compiler, one with c23 #embed (default: src/tools/findcc.sh). CFLAGS adds to -O2
 #
 # the build is three steps: automap sizes the map to the program and writes the
 # genome (the compiled program image) for it; the micro core and its linux port
@@ -16,13 +16,13 @@
 # the same image without the static link.
 set -e
 here="$(cd "$(dirname "$0")/../.." && pwd)"
-CC=${CC:-cc}
+CC=${CC:-$(sh "$here/src/tools/findcc.sh")}
 out=""; keep=0
 while [ $# -gt 0 ]; do
 	case "$1" in
 		-o) [ $# -ge 2 ] || { echo "zcc: -o needs a name" >&2; exit 2; }; out="$2"; shift 2 ;;
 		-k) keep=1; shift ;;
-		-h|--help) printf '%s\n' 'usage: src/tools/zcc [-o OUT] [-k] FILE.zc' 'compiles a source file into a standalone binary; links statically where supported.' 'options:' '  -o OUT      output binary path; defaults to the source basename without .zc' '  -k          keep the temporary build directory' '  --help, -h  show this help and exit' 'environment: CC selects the c compiler; CFLAGS adds compiler flags.'; exit 0 ;;
+		-h|--help) printf '%s\n' 'usage: src/tools/zcc [-o OUT] [-k] FILE.zc' 'compiles a source file into a standalone binary; links statically where supported.' 'options:' '  -o OUT      output binary path; defaults to the source basename without .zc' '  -k          keep the temporary build directory' '  --help, -h  show this help and exit' 'environment: CC selects the c compiler (one with #embed); CFLAGS adds compiler flags.'; exit 0 ;;
 		-*) echo "zcc: unknown option $1" >&2; exit 2 ;;
 		*) break ;;
 	esac
@@ -41,7 +41,7 @@ trap cleanup EXIT
 # the map and the genome for this program only
 ( cd "$here" && bash src/tools/automap.sh run "$work/run" src/runtime/run.zc "$abs" ) >/dev/null
 cp "$here/src/micro/micro.c" "$here/src/micro/micro_port.h" "$here/src/micro/port_linux.c" \
-	"$here/src/core/fops.h" "$here/src/core/bops.h" "$here/src/core/stack.h" "$work/run/"
+	"$here/src/core/fops.h" "$here/src/core/bops.h" "$here/src/core/stack.h" "$here/src/core/genome.h" "$work/run/"
 
 # static where the toolchain allows it; a plain link otherwise, with a note
 static=-static
diff --git a/src/web/build.sh b/src/web/build.sh
index 7443f46..1f2cfae 100755
--- a/src/web/build.sh
+++ b/src/web/build.sh
@@ -1,16 +1,23 @@
 #!/bin/bash
-# builds src/web/zc.wasm (or the path given as the first argument): the microcore, with the compiler genome inside, as
-# WebAssembly. needs clang with the wasm32 target and wasm-ld. the page
-# (src/web/index.html) loads it next to src/web/zc.js.
+# builds the browser compiler: the microcore with the compiler genome inside, as
+# WebAssembly, written to build/web/zc.wasm (or the path given as the first
+# argument). the page (src/web/index.html) loads it next to zc.js; `make web`
+# copies both beside it, so build/web/ is the whole site. needs clang with the
+# wasm32 target, #embed and wasm-ld, and the genome from `make genome`.
 set -e
 case "${1:-}" in
-    --help|-h) printf '%s\n' 'usage: src/web/build.sh [OUTFILE.wasm]' 'builds the browser compiler vm; defaults to src/web/zc.wasm.' 'requires clang with wasm32 support and wasm-ld.'; exit 0 ;;
+    --help|-h) printf '%s\n' 'usage: src/web/build.sh [OUTFILE.wasm]' 'builds the browser compiler vm; defaults to build/web/zc.wasm.' 'requires clang with wasm32 and #embed support, and wasm-ld.' 'environment: WASM_CC selects the compiler; GENOME_DIR holds genome.bin (build/core); MAP_DIR holds its memmap.h (build/core/map).'; exit 0 ;;
     -*) echo "web build: unknown option $1; use --help for usage" >&2; exit 2 ;;
 esac
 cd "$(dirname "$0")/../.."
-clang --target=wasm32 -O2 -w -fwrapv -nostdlib -fno-builtin -mbulk-memory -DJTYPE=int \
-	-Isrc/core -Isrc/micro src/micro/micro.c src/web/port_wasm.c \
+OUT=${1:-build/web/zc.wasm}
+WASM_CC=${WASM_CC:-$(sh src/tools/findcc.sh --wasm)}
+GENOME_DIR=${GENOME_DIR:-build/core}; MAP_DIR=${MAP_DIR:-build/core/map}
+[ -f "$GENOME_DIR/genome.bin" ] || { echo "web build: no $GENOME_DIR/genome.bin; run make genome first" >&2; exit 1; }
+mkdir -p "$(dirname "$OUT")"
+"$WASM_CC" --target=wasm32 -O2 -w -fwrapv -nostdlib -fno-builtin -mbulk-memory -DJTYPE=int \
+	-Isrc/core -I"$MAP_DIR" --embed-dir="$GENOME_DIR" -Isrc/micro src/micro/micro.c src/web/port_wasm.c \
 	-Wl,--no-entry -Wl,--export=wasm_input -Wl,--export=wasm_input_cap -Wl,--export=wasm_set_input -Wl,--export=wasm_run \
 	-Wl,--export=memory -Wl,--allow-undefined -Wl,--initial-memory=33554432 -Wl,-z,stack-size=65536 \
-	-o "${1:-src/web/zc.wasm}"
-ls -l "${1:-src/web/zc.wasm}"
+	-o "$OUT"
+ls -l "$OUT"
diff --git a/tests/bench/bench.sh b/tests/bench/bench.sh
index ab6b07d..65f455e 100644
--- a/tests/bench/bench.sh
+++ b/tests/bench/bench.sh
@@ -2,13 +2,15 @@
 # o3 against plain code: each kernel in tests/programs/bench.zc on each backend, with
 # the time to start up and compile (the 'z' run) taken off. needs bc.
 cd "$(dirname "$0")/../.."; T=$(mktemp -d); trap 'rm -rf $T' EXIT
-gcc -O2 -w -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -o $T/zy
+CC=${CC:-$(sh src/tools/findcc.sh)} || exit 1
+make -s build/core/genome.bin || exit 1
+$CC -O2 -w -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core/map --embed-dir=build/core -o $T/zy
 vms=("$T/zy"); names=("interp")
 if command -v llvm-config >/dev/null; then
-	gcc -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) src/core/core.c src/core/io_linux.c -Isrc/core -o $T/zyl $(llvm-config --ldflags --libs) && { vms+=("$T/zyl"); names+=("llvm"); }
+	$CC -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core/map --embed-dir=build/core -o $T/zyl $(llvm-config --ldflags --libs) && { vms+=("$T/zyl"); names+=("llvm"); }
 fi
 if command -v aarch64-linux-gnu-gcc >/dev/null && command -v qemu-aarch64 >/dev/null; then
-	aarch64-linux-gnu-gcc -O2 -w -DJTYPE=int -static src/core/core.c src/core/io_linux.c -Isrc/core -o $T/zyj && { vms+=("qemu-aarch64 $T/zyj"); names+=("arm64 (qemu)"); }
+	aarch64-linux-gnu-gcc -O2 -w -DJTYPE=int -static src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core/map --embed-dir=build/core -o $T/zyj && { vms+=("qemu-aarch64 $T/zyj"); names+=("arm64 (qemu)"); }
 fi
 # seconds per run of kernel $2 on vm $1: the slope between $3 runs and 1 run,
 # best of three each, so starting up and compiling cancel out
diff --git a/tests/bench/bench_bytes.sh b/tests/bench/bench_bytes.sh
index acff074..775b71d 100644
--- a/tests/bench/bench_bytes.sh
+++ b/tests/bench/bench_bytes.sh
@@ -4,16 +4,18 @@ set -e
 # in the process. the slope between 1 repetition and N drops startup.
 # prints: backend  ms/rep  checksum
 cd "$(dirname "$0")/../.."
+CC=${CC:-$(sh src/tools/findcc.sh)} || exit 1
+make -s build/core/genome.bin || exit 1
 T=$(mktemp -d)
 trap 'rm -rf "$T"' EXIT
-gcc -O2 -w src/tools/genmap.c -o "$T/genmap" || exit 1
+$CC -O2 -w src/tools/genmap.c -o "$T/genmap" || exit 1
 GENMAP="$T/genmap" bash src/tools/automap.sh run "$T/run" src/runtime/run.zc tests/programs/bench_bytes.zc >/dev/null || exit 1
-cp src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h "$T/run/"
-gcc -O2 -w -DJTYPE=int "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zy" || exit 1
-gcc -O2 -w "$T/run/micro.c" "$T/run/port_linux.c" -o "$T/zym" || exit 1
+cp src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h "$T/run/"
+$CC -O2 -w -DJTYPE=int "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zy" || exit 1
+$CC -O2 -w "$T/run/micro.c" "$T/run/port_linux.c" -o "$T/zym" || exit 1
 vms=("$T/zy" "$T/zym"); names=("interp" "micro")
 if command -v llvm-config >/dev/null; then
-	gcc -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zyl" $(llvm-config --ldflags --libs) \
+	$CC -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zyl" $(llvm-config --ldflags --libs) \
 		&& { vms+=("$T/zyl"); names+=("llvm"); }
 fi
 if command -v aarch64-linux-gnu-gcc >/dev/null && command -v qemu-aarch64 >/dev/null; then
diff --git a/tests/bench/bench_float.sh b/tests/bench/bench_float.sh
index 794e976..4ebfbe4 100644
--- a/tests/bench/bench_float.sh
+++ b/tests/bench/bench_float.sh
@@ -5,17 +5,19 @@
 # this does not bootstrap the compiler. each kernel is poly() of 20000,
 # and (int) of one call is 59997.
 cd "$(dirname "$0")/../.."
+CC=${CC:-$(sh src/tools/findcc.sh)} || exit 1
+make -s build/core/genome.bin || exit 1
 T=$(mktemp -d)
 trap 'rm -rf "$T"' EXIT
-gcc -O2 -w -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -o "$T/zy" || exit 1
+$CC -O2 -w -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core/map --embed-dir=build/core -o "$T/zy" || exit 1
 vms=("$T/zy"); names=("interp")
-gcc -O2 -w src/micro/micro.c src/micro/port_linux.c -Isrc/core -Isrc/micro -o "$T/zym" && { vms+=("$T/zym"); names+=("micro"); }
+$CC -O2 -w src/micro/micro.c src/micro/port_linux.c -Isrc/core -Ibuild/core/map --embed-dir=build/core -Isrc/micro -o "$T/zym" && { vms+=("$T/zym"); names+=("micro"); }
 if command -v llvm-config >/dev/null; then
-	gcc -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) src/core/core.c src/core/io_linux.c -Isrc/core -o "$T/zyl" $(llvm-config --ldflags --libs) \
+	$CC -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core/map --embed-dir=build/core -o "$T/zyl" $(llvm-config --ldflags --libs) \
 		&& { vms+=("$T/zyl"); names+=("llvm"); }
 fi
 if command -v aarch64-linux-gnu-gcc >/dev/null && command -v qemu-aarch64 >/dev/null; then
-	aarch64-linux-gnu-gcc -O2 -w -DJTYPE=int -static src/core/core.c src/core/io_linux.c -Isrc/core -o "$T/zyj" \
+	aarch64-linux-gnu-gcc -O2 -w -DJTYPE=int -static src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core/map --embed-dir=build/core -o "$T/zyj" \
 		&& { vms+=("qemu-aarch64 $T/zyj"); names+=("arm64"); }
 fi
 src=$(cat tests/programs/fbench.zc)
diff --git a/tests/bench/bench_share.sh b/tests/bench/bench_share.sh
index b449e09..5cb1bfd 100644
--- a/tests/bench/bench_share.sh
+++ b/tests/bench/bench_share.sh
@@ -3,18 +3,19 @@
 # resident compiler is not in the process. the slope between 1 repetition
 # and N drops startup. prints: backend  ms/rep  checksum
 cd "$(dirname "$0")/../.."
+CC=${CC:-$(sh src/tools/findcc.sh)} || exit 1
 T=$(mktemp -d)
 trap 'rm -rf "$T"' EXIT
-gcc -O2 -w src/tools/genmap.c -o "$T/genmap" || exit 1
+$CC -O2 -w src/tools/genmap.c -o "$T/genmap" || exit 1
 "$T/genmap" --preset run -o "$T/run" >/dev/null || exit 1
-cp src/tools/zc0.c src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h "$T/run/"
-gcc -O1 -w "$T/run/zc0.c" -o "$T/zc0" || exit 1
-cat "$T/run/rt.zc" src/runtime/run.zc tests/programs/bench_share.zc | "$T/zc0" > "$T/run/genome.h" || exit 1
-gcc -O2 -w -DJTYPE=int "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zy" || exit 1
-gcc -O2 -w "$T/run/micro.c" "$T/run/port_linux.c" -o "$T/zym" || exit 1
+cp src/tools/zc0.c src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h "$T/run/"
+$CC -O1 -w "$T/run/zc0.c" -o "$T/zc0" || exit 1
+cat "$T/run/rt.zc" src/core/core.zc src/runtime/run.zc tests/programs/bench_share.zc | "$T/zc0" > "$T/run/genome.bin" || exit 1
+$CC -O2 -w -DJTYPE=int "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zy" || exit 1
+$CC -O2 -w "$T/run/micro.c" "$T/run/port_linux.c" -o "$T/zym" || exit 1
 vms=("$T/zy" "$T/zym"); names=("interp" "micro")
 if command -v llvm-config >/dev/null; then
-	gcc -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zyl" $(llvm-config --ldflags --libs) \
+	$CC -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zyl" $(llvm-config --ldflags --libs) \
 		&& { vms+=("$T/zyl"); names+=("llvm"); }
 fi
 if command -v aarch64-linux-gnu-gcc >/dev/null && command -v qemu-aarch64 >/dev/null; then
diff --git a/tests/bench/bench_strings.sh b/tests/bench/bench_strings.sh
index c353342..b14bf57 100644
--- a/tests/bench/bench_strings.sh
+++ b/tests/bench/bench_strings.sh
@@ -3,18 +3,19 @@
 # resident compiler is not in the process. the slope between 1 repetition
 # and N drops startup. prints: backend  ms/rep  checksum
 cd "$(dirname "$0")/../.."
+CC=${CC:-$(sh src/tools/findcc.sh)} || exit 1
 T=$(mktemp -d)
 trap 'rm -rf "$T"' EXIT
-gcc -O2 -w src/tools/genmap.c -o "$T/genmap" || exit 1
+$CC -O2 -w src/tools/genmap.c -o "$T/genmap" || exit 1
 "$T/genmap" --preset run -o "$T/run" >/dev/null || exit 1
-cp src/tools/zc0.c src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h "$T/run/"
-gcc -O1 -w "$T/run/zc0.c" -o "$T/zc0" || exit 1
-cat "$T/run/rt.zc" src/runtime/run.zc tests/programs/bench_strings.zc | "$T/zc0" > "$T/run/genome.h" || exit 1
-gcc -O2 -w -DJTYPE=int "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zy" || exit 1
-gcc -O2 -w "$T/run/micro.c" "$T/run/port_linux.c" -o "$T/zym" || exit 1
+cp src/tools/zc0.c src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h "$T/run/"
+$CC -O1 -w "$T/run/zc0.c" -o "$T/zc0" || exit 1
+cat "$T/run/rt.zc" src/core/core.zc src/runtime/run.zc tests/programs/bench_strings.zc | "$T/zc0" > "$T/run/genome.bin" || exit 1
+$CC -O2 -w -DJTYPE=int "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zy" || exit 1
+$CC -O2 -w "$T/run/micro.c" "$T/run/port_linux.c" -o "$T/zym" || exit 1
 vms=("$T/zy" "$T/zym"); names=("interp" "micro")
 if command -v llvm-config >/dev/null; then
-	gcc -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zyl" $(llvm-config --ldflags --libs) \
+	$CC -O2 -w -DJTYPE=int -DZYLLVM $(llvm-config --cflags) "$T/run/core.c" "$T/run/io_linux.c" -o "$T/zyl" $(llvm-config --ldflags --libs) \
 		&& { vms+=("$T/zyl"); names+=("llvm"); }
 fi
 if command -v aarch64-linux-gnu-gcc >/dev/null && command -v qemu-aarch64 >/dev/null; then
diff --git a/tests/bench/run.py b/tests/bench/run.py
index cb28b92..7f7ea6f 100755
--- a/tests/bench/run.py
+++ b/tests/bench/run.py
@@ -79,18 +79,21 @@ def machine_lines():
 def build(td):
     td = Path(td)
     log("building vms")
+    need(["make", "-s", "build/core/genome.bin"], cwd=ROOT)
+    cc = os.environ.get("CC") or subprocess.check_output(["sh", "src/tools/findcc.sh"], cwd=ROOT, text=True).strip()
+    core = ["-Isrc/core", "-Ibuild/core/map", "--embed-dir=build/core"]
     zy = td / "zy"
-    need(["gcc", "-O3", "-w", "-DJTYPE=int", "src/core/core.c", "src/core/io_linux.c", "-Isrc/core", "-o", str(zy)], cwd=ROOT)
+    need([cc, "-O3", "-w", "-DJTYPE=int", "src/core/core.c", "src/core/io_linux.c", *core, "-o", str(zy)], cwd=ROOT)
     vms = {"interp": [str(zy)]}
     if shutil.which("llvm-config"):
         cflags = subprocess.check_output(["llvm-config", "--cflags"], text=True).split()
         ld = subprocess.check_output(["llvm-config", "--ldflags", "--libs"], text=True).split()
         zyl = td / "zyl"
-        need(["gcc", "-O3", "-w", "-DJTYPE=int", "-DZYLLVM", *cflags, "src/core/core.c", "src/core/io_linux.c", "-Isrc/core", "-o", str(zyl), *ld], cwd=ROOT)
+        need([cc, "-O3", "-w", "-DJTYPE=int", "-DZYLLVM", *cflags, "src/core/core.c", "src/core/io_linux.c", *core, "-o", str(zyl), *ld], cwd=ROOT)
         vms["llvm"] = [str(zyl)]
     if shutil.which("aarch64-linux-gnu-gcc") and shutil.which("qemu-aarch64"):
         zyj = td / "zyj"
-        need(["aarch64-linux-gnu-gcc", "-O3", "-w", "-DJTYPE=int", "-static", "src/core/core.c", "src/core/io_linux.c", "-Isrc/core", "-o", str(zyj)], cwd=ROOT)
+        need(["aarch64-linux-gnu-gcc", "-O3", "-w", "-DJTYPE=int", "-static", "src/core/core.c", "src/core/io_linux.c", *core, "-o", str(zyj)], cwd=ROOT)
         vms["arm64"] = ["qemu-aarch64", str(zyj)]
     log("building C")
     bins = {}
diff --git a/tests/drivers/actor_image_test.py b/tests/drivers/actor_image_test.py
index 9df8828..5b815f2 100644
--- a/tests/drivers/actor_image_test.py
+++ b/tests/drivers/actor_image_test.py
@@ -1,12 +1,16 @@
 #!/usr/bin/env python3
 # source syntax callbacks execute in the host while actor code is emitted separately.
 from pathlib import Path
+import sys
 import argparse
 import subprocess
 import tempfile
+sys.dont_write_bytecode = True  # importing imagekit must not leave __pycache__ in the tree
+from imagekit import micro_image
 
 parser = argparse.ArgumentParser()
-parser.add_argument('--host', default='bin/zy')
+parser.add_argument('--host', default='build/bin/zy')
+parser.add_argument('--mkgenome', default='build/bin/mkgenome')
 parser.add_argument('--case', default='')
 args = parser.parse_args()
 prefix = b''.join(Path(f).read_bytes() + b'\n' for f in ('src/runtime/rt.zc', 'src/core/core.zc', 'src/runtime/run.zc'))
@@ -18,11 +22,8 @@ for name, source, expected in cases:
         directory = Path(work)
         compiled = subprocess.run([args.host], input=Path('src/tools/build.zc').read_bytes() + b'`' + prefix + source.encode(), capture_output=True, timeout=30)
         assert compiled.returncode == 0 and len(compiled.stdout) >= 56 and not compiled.stdout.startswith(b'zc:'), (name, compiled.stdout[:2000], compiled.stderr)
-        header = subprocess.run(['bin/mkgenome'], input=compiled.stdout, capture_output=True, check=True)
-        (directory / 'genome.h').write_bytes(header.stdout)
-        for f in ('src/core/memmap.h', 'src/core/fops.h', 'src/core/bops.h', 'src/core/stack.h', 'src/micro/micro.c', 'src/micro/micro_port.h', 'src/micro/port_linux.c'):
-            (directory / Path(f).name).write_bytes(Path(f).read_bytes())
-        subprocess.run(['cc', '-O2', '-w', '-fwrapv', '-pthread', '-DZY_THREADS', str(directory / 'micro.c'), str(directory / 'port_linux.c'), '-I' + work, '-o', str(directory / 'image')], check=True, timeout=30)
-        result = subprocess.run([str(directory / 'image')], capture_output=True, timeout=12)
+        image = subprocess.run([args.mkgenome], input=compiled.stdout, capture_output=True, check=True)
+        binary = micro_image(directory, image.stdout)
+        result = subprocess.run([str(binary)], capture_output=True, timeout=12)
         assert result.returncode == 0 and result.stdout == expected, (name, result.returncode, result.stdout, result.stderr)
         print('ok   actor compiler-free image: ' + name)
diff --git a/tests/drivers/actor_test.py b/tests/drivers/actor_test.py
index 43a110f..0cfa51f 100644
--- a/tests/drivers/actor_test.py
+++ b/tests/drivers/actor_test.py
@@ -6,7 +6,7 @@ import subprocess
 import time
 
 parser = argparse.ArgumentParser()
-parser.add_argument('vm', nargs='?', default='bin/zy')
+parser.add_argument('vm', nargs='?', default='build/bin/zy')
 parser.add_argument('--case', default='')
 parser.add_argument('--library', default='')
 args = parser.parse_args()
diff --git a/tests/drivers/analysis_cache_test.js b/tests/drivers/analysis_cache_test.js
index 3ffde33..88bb4bd 100644
--- a/tests/drivers/analysis_cache_test.js
+++ b/tests/drivers/analysis_cache_test.js
@@ -1,4 +1,6 @@
 // Repeated replies use cached results; edits, include updates and reopen invalidate them.
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert'), cp = require('child_process'), path = require('path');
 const uri = 'file:///cache/main.zc', text = 'include "dep.zc";\nfn main() { int n = 7; return n + value(); }';
 const msgs = []; let id = 1;
@@ -26,7 +28,7 @@ if (process.argv[2] === '--wasm' || process.argv[2] === '--vm') {
     const p = (wasm ? host.wasmProcess : host.vmProcess)(path.resolve(process.argv[3]), { log: () => {} });
     const chunks = []; p.stdout.on('data', d => chunks.push(d)); msgs.forEach(m => p.stdin.write(frame(m))); out = Buffer.concat(chunks);
 } else {
-    const r = cp.spawnSync(process.argv[2], process.argv.slice(3), { input: Buffer.concat(msgs.map(frame)), timeout: 60000, maxBuffer: 16 << 20 });
+    const r = cp.spawnSync(process.argv[2], process.argv.slice(3), { input: Buffer.concat(msgs.map(frame)), timeout: 60000 * TIMEOUT_SCALE, maxBuffer: 16 << 20 });
     assert.strictEqual(r.status, 0, String(r.stderr)); out = r.stdout;
 }
 const replies = new Map();
diff --git a/tests/drivers/array_methods_test.py b/tests/drivers/array_methods_test.py
index 82fef67..bf6e670 100644
--- a/tests/drivers/array_methods_test.py
+++ b/tests/drivers/array_methods_test.py
@@ -5,7 +5,7 @@ import re
 import subprocess
 
 parser = argparse.ArgumentParser()
-parser.add_argument('host', nargs='?', default='bin/zy')
+parser.add_argument('host', nargs='?', default='build/bin/zy')
 parser.add_argument('--case', default='')
 args = parser.parse_args()
 
diff --git a/tests/drivers/cli_help_test.py b/tests/drivers/cli_help_test.py
index 1b32fa4..97eebea 100644
--- a/tests/drivers/cli_help_test.py
+++ b/tests/drivers/cli_help_test.py
@@ -7,15 +7,16 @@ from pathlib import Path
 
 parser = argparse.ArgumentParser()
 parser.add_argument('--group', choices=['binaries', 'scripts', 'js', 'all'], default='all')
-parser.add_argument('--bin-dir', default='bin')
+parser.add_argument('--bin-dir', default='build/bin')
+parser.add_argument('--js-dir', default='build/js')
 args = parser.parse_args()
 commands = []
 if args.group in ('binaries', 'all'):
     commands += [[str(Path(args.bin_dir) / name)] for name in ['zy', 'zym', 'zclsp', 'zc0', 'mkgenome', 'genmap']]
 if args.group in ('scripts', 'all'):
-    commands += [['bash', name] for name in ['tinyvm.sh', 'src/tools/zcc', 'src/tools/automap.sh', 'src/tools/embed.sh', 'src/tools/mklsp.sh', 'src/tools/mklspwasm.sh', 'src/tools/mkvsix.sh', 'src/web/build.sh', 'src/baremetal/run.sh']]
+    commands += [['bash', name] for name in ['tinyvm.sh', 'src/tools/zcc', 'src/tools/automap.sh', 'src/tools/findcc.sh', 'src/tools/bootstrap-check.sh', 'src/tools/mklsp.sh', 'src/tools/mklspwasm.sh', 'src/tools/mkvsix.sh', 'src/web/build.sh', 'src/baremetal/run.sh']]
 if args.group in ('js', 'all'):
-    commands += [['node', name] for name in ['src/js/tinyvm.js', 'src/js/extract_genome.js', 'src/js/extract_lsp.js']]
+    commands += [['node', name] for name in [str(Path(args.js_dir) / 'tinyvm.js'), 'src/js/mklayout.js', 'src/js/extract_lsp.js']]
 
 def invoke(command, option):
     # keep stdin open: help and rejected options must finish without reading it.
diff --git a/tests/drivers/completion_test.js b/tests/drivers/completion_test.js
index 22c5fa5..f1ee5e6 100644
--- a/tests/drivers/completion_test.js
+++ b/tests/drivers/completion_test.js
@@ -1,5 +1,7 @@
 // compiler-backed completion, including incomplete source and position-aware lifetimes.
 // usage: node tests/drivers/completion_test.js path/to/zclsp [server arguments]
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const path = require('path');
@@ -25,7 +27,7 @@ function complete(source, extra = []) {
         for (const m of msgs) proc.stdin.write(frame(m));
         output = Buffer.concat(chunks);
     } else {
-        const r = cp.spawnSync(process.argv[2], process.argv.slice(3), { input: Buffer.concat(msgs.map(frame)), timeout: 30000, maxBuffer: 32 << 20 });
+        const r = cp.spawnSync(process.argv[2], process.argv.slice(3), { input: Buffer.concat(msgs.map(frame)), timeout: 30000 * TIMEOUT_SCALE, maxBuffer: 32 << 20 });
         assert.strictEqual(r.status, 0, String(r.stderr)); output = r.stdout;
     }
     let b = output; const replies = [];
diff --git a/tests/drivers/core_lsp_test.js b/tests/drivers/core_lsp_test.js
index 983f9aa..c3c01aa 100644
--- a/tests/drivers/core_lsp_test.js
+++ b/tests/drivers/core_lsp_test.js
@@ -1,4 +1,6 @@
 // check maintained zc sources through the editor document protocol, one file at a time.
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const fs = require('fs');
 const cp = require('child_process');
@@ -23,7 +25,7 @@ for (const file of files) {
         { jsonrpc: '2.0', id: 3, method: 'shutdown', params: null },
         { jsonrpc: '2.0', method: 'exit' },
     ];
-    const result = cp.spawnSync(target, [], { input: Buffer.concat(messages.map(frame)), timeout: 30000, maxBuffer: 32 << 20 });
+    const result = cp.spawnSync(target, [], { input: Buffer.concat(messages.map(frame)), timeout: 30000 * TIMEOUT_SCALE, maxBuffer: 32 << 20 });
     assert.strictEqual(result.status, 0, file + ': ' + result.stderr);
     let data = result.stdout;
     const replies = [];
diff --git a/tests/drivers/enhancement_backends_test.py b/tests/drivers/enhancement_backends_test.py
index b7d553b..ddfee1b 100644
--- a/tests/drivers/enhancement_backends_test.py
+++ b/tests/drivers/enhancement_backends_test.py
@@ -9,7 +9,7 @@ source = (root / 'tests/programs/enhance.zc').read_text()
 source = source.replace('i < 5000', 'i < 200')
 source += '\n'
 reference = None
-for command in [['bin/zy'], ['bin/zym'], ['node', 'src/js/tinyvm.js']]:
+for command in [['build/bin/zy'], ['build/bin/zym'], ['node', 'src/js/tinyvm.js']]:
     result = subprocess.run(command, input=source, text=True, capture_output=True, timeout=25)
     assert result.returncode == 0 and result.stdout and 'zc:' not in result.stdout, (command, result.returncode, result.stdout, result.stderr)
     if reference is None:
@@ -20,7 +20,7 @@ for command in [['bin/zy'], ['bin/zym'], ['node', 'src/js/tinyvm.js']]:
 source = '''o3 int increment(int value) { return value + 1; }
 fn main() { put_n(increment(6)); put_c(32); put_n(17 / 5); put_c(32); put_n(17 % 5); put_c(10); return 0; }
 '''
-for command in [['bin/zy'], ['bin/zym'], ['node', 'src/js/tinyvm.js']]:
+for command in [['build/bin/zy'], ['build/bin/zym'], ['node', 'src/js/tinyvm.js']]:
     result = subprocess.run(command, input=source, text=True, capture_output=True, timeout=15)
     assert result.returncode == 0 and result.stdout == '7 3 2\n', (command, result.stdout, result.stderr)
     print('ok   optimizer descriptors preserve portable division slots: ' + command[0])
@@ -39,7 +39,7 @@ fn main() {
  put_n(installed); put_c(32); put_n(first); put_c(32); put_n(rejected); put_c(32); put_n(second); put_c(10); return 0;
 }
 '''
-for command in [['bin/zy'], ['bin/zym'], ['node', 'src/js/tinyvm.js']]:
+for command in [['build/bin/zy'], ['build/bin/zym'], ['node', 'src/js/tinyvm.js']]:
     result = subprocess.run(command, input=source, text=True, capture_output=True, timeout=15)
     assert result.returncode == 0 and result.stdout == '1 22 1 22\n', (command, result.stdout, result.stderr)
     print('ok   replacing a built-in slot and rejecting a bad recipe: ' + command[0])
diff --git a/tests/drivers/ext_cache_test.js b/tests/drivers/ext_cache_test.js
index f389fcc..93caf94 100644
--- a/tests/drivers/ext_cache_test.js
+++ b/tests/drivers/ext_cache_test.js
@@ -5,14 +5,25 @@
 // starts; a change to an included file is checked again; putting it back is
 // answered from the cache.
 //
-//   node tests/drivers/ext_cache_test.js
+//   node tests/drivers/ext_cache_test.js [server-dir]
+//
+// the server directory holds what the packaged extension carries in server/:
+// lsp.wasm, or tinyvm.js, layout.js, lsp.json and lsp.bin (the default is
+// build/editors/vscode/server, which src/tools/mkvsix.sh fills). the extension is
+// copied with that server into a scratch directory, since the tree has none.
 
 const fs = require('fs');
 const os = require('os');
 const path = require('path');
 const Module = require('module');
 
-const client = path.join(__dirname, '..', '..', 'editors', 'vscode', 'client');
+const serverDir = path.resolve(process.argv[2] || path.join(__dirname, '..', '..', 'build', 'editors', 'vscode', 'server'));
+if (!fs.existsSync(serverDir)) { console.log('FAIL no server directory at ' + serverDir); process.exit(1); }
+const staged = fs.mkdtempSync(path.join(os.tmpdir(), 'zc-extension-'));
+fs.cpSync(path.join(__dirname, '..', '..', 'editors', 'vscode'), staged, { recursive: true });
+fs.cpSync(serverDir, path.join(staged, 'server'), { recursive: true });
+process.on('exit', () => fs.rmSync(staged, { recursive: true, force: true }));
+const client = path.join(staged, 'client');
 
 // the vscode module, as far as the client uses it
 const world = { lines: [], sets: [], listeners: {}, watchers: [], textDocuments: [], saved: undefined, root: '' };
diff --git a/tests/drivers/float_backends_test.py b/tests/drivers/float_backends_test.py
index cdcf48b..65901e2 100644
--- a/tests/drivers/float_backends_test.py
+++ b/tests/drivers/float_backends_test.py
@@ -4,7 +4,7 @@ import pathlib
 import subprocess
 
 root = pathlib.Path(__file__).resolve().parents[2]
-commands = [['bin/zy'], ['bin/zym'], ['node', 'src/js/tinyvm.js']]
+commands = [['build/bin/zy'], ['build/bin/zym'], ['node', 'src/js/tinyvm.js']]
 sources = [(root / 'tests/programs/float.zc').read_text(), '''include rt; fn render(bits, precision, mode) { asm { bits @ precision @ mode @ #1236 } return 0; }
 fn convert(bits) { return asm { bits @ #1218 }; }
 fn main() {
diff --git a/tests/drivers/fuzz_compiler.py b/tests/drivers/fuzz_compiler.py
index 512ec26..0fe0d27 100644
--- a/tests/drivers/fuzz_compiler.py
+++ b/tests/drivers/fuzz_compiler.py
@@ -1,17 +1,23 @@
 #!/usr/bin/env python3
 """Deterministic grammar fuzzing for the parser, runtime, and ownership paths.
 
-Usage: python3 tests/drivers/fuzz_compiler.py [path/to/zy] [path/to/zym] [--js]
+Usage: python3 tests/drivers/fuzz_compiler.py [path/to/zy] [path/to/zym] [--js [path/to/tinyvm.js]]
+(--js alone runs build/js/tinyvm.js, from make js)
 """
 import random
 import subprocess
 import sys
 
 
-args = [arg for arg in sys.argv[1:] if arg != "--js"]
-js = "--js" in sys.argv[1:]
-zy = args[0] if len(args) > 0 else "bin/zy"
-zym = args[1] if len(args) > 1 else "bin/zym"
+argv = sys.argv[1:]
+js = None
+if "--js" in argv:
+    k = argv.index("--js")
+    del argv[k]
+    js = argv.pop(k) if k < len(argv) and argv[k].endswith(".js") else "build/js/tinyvm.js"
+args = argv
+zy = args[0] if len(args) > 0 else "build/bin/zy"
+zym = args[1] if len(args) > 1 else "build/bin/zym"
 rng = random.Random(0x5A17)
 values = []
 library_values = []
@@ -33,26 +39,26 @@ def expr(depth):
     return f"({left} {op} {right})", value
 
 
-lines = ["include std;", "fn churn(n) {", " int i = 0;", " while (i < n) {", "  { int* p = new(int); *p = i; }", "  i++;", " }", " return 0;", "}", "fn stable() { return 73; }", "fn main() {", " let base = live_objects();"]
+lines = ["namespace;", "include rt, run, std;", "fn churn(n) {", " int i = 0;", " while (i < n) {", "  { int* p = rt.new(int); *p = i; }", "  i++;", " }", " return 0;", "}", "fn stable() { return 73; }", "fn main() {", " let base = rt.live_objects();"]
 for _ in range(128):
     source, value = expr(4)
-    lines.append(f" put_n({source}); put_c(32);")
+    lines.append(f" rt.put_n({source}); rt.put_c(32);")
     values.append(value)
 for _ in range(32):
     a = "".join(rng.choice("abc") for _ in range(rng.randrange(11)))
     b = "".join(rng.choice("abc") for _ in range(rng.randrange(6)))
-    lines.append(f' put_n(Text.len("{a}")); put_c(32); put_n(Text.eq("{a}", "{b}")); put_c(32);')
-    lines.append(f' put_n(Text.starts("{a}", "{b}")); put_c(32); put_n(Text.ends("{a}", "{b}")); put_c(32); put_n(Text.find("{a}", "{b}")); put_c(32);')
-    lines.append(f' put_n(Bytes.len(b"{a}")); put_c(32); put_n(Bytes.eq(b"{a}", b"{b}")); put_c(32);')
-    lines.append(f' put_n(Bytes.starts(b"{a}", b"{b}")); put_c(32); put_n(Bytes.ends(b"{a}", b"{b}")); put_c(32); put_n(Bytes.find(b"{a}", b"{b}")); put_c(32);')
+    lines.append(f' rt.put_n(std.Text.len("{a}")); rt.put_c(32); rt.put_n(std.Text.eq("{a}", "{b}")); rt.put_c(32);')
+    lines.append(f' rt.put_n(std.Text.starts("{a}", "{b}")); rt.put_c(32); rt.put_n(std.Text.ends("{a}", "{b}")); rt.put_c(32); rt.put_n(std.Text.find("{a}", "{b}")); rt.put_c(32);')
+    lines.append(f' rt.put_n(std.Bytes.len(b"{a}")); rt.put_c(32); rt.put_n(std.Bytes.eq(b"{a}", b"{b}")); rt.put_c(32);')
+    lines.append(f' rt.put_n(std.Bytes.starts(b"{a}", b"{b}")); rt.put_c(32); rt.put_n(std.Bytes.ends(b"{a}", b"{b}")); rt.put_c(32); rt.put_n(std.Bytes.find(b"{a}", b"{b}")); rt.put_c(32);')
     library_values += [len(a), int(a == b), int(a.startswith(b)), int(a.endswith(b)), a.find(b), len(a.encode()), int(a == b), int(a.startswith(b)), int(a.endswith(b)), a.find(b)]
 lines += [
-    " churn(300); gc(); put_n(live_objects() - base); put_c(32);",
-    ' char* source = "fn f() { return 7; }"; let parsed = tokens(source);',
-    ' put_n(parsed[0] > 0); put_c(32); put_n(eq_w(source, "fn f() { return 7; }")); put_c(32);',
+    " churn(300); rt.gc(); rt.put_n(rt.live_objects() - base); rt.put_c(32);",
+    ' char* source = "fn f() { return 7; }"; let parsed = run.tokens(source);',
+    ' rt.put_n(parsed[0] > 0); rt.put_c(32); rt.put_n(rt.eq_w(source, "fn f() { return 7; }")); rt.put_c(32);',
     ' char* eval_source = "return 42;"; int e = 0;',
-    ' while (e < 16) { let q = tokens(eval_source); put_n(eval(q)); put_c(32); e++; }',
-    ' put_n(stable()); put_c(32); put_n(eq_w(eval_source, "return 42;")); put_c(10);',
+    ' while (e < 16) { let q = run.tokens(eval_source); rt.put_n(run.eval(q)); rt.put_c(32); e++; }',
+    ' rt.put_n(stable()); rt.put_c(32); rt.put_n(rt.eq_w(eval_source, "return 42;")); rt.put_c(10);',
     " return 0;",
     "}",
 ]
@@ -78,7 +84,7 @@ def run(binary):
 
 hosts = [(zy, [zy]), (zym, [zym])]
 if js:
-    hosts.append(("javascript", ["node", "src/js/tinyvm.js"]))
+    hosts.append(("javascript", ["node", js]))
 outputs = [run(command) for _, command in hosts]
 if any(output != outputs[0] for output in outputs[1:]):
     raise SystemExit("compiler hosts disagreed on deterministic fuzz output")
diff --git a/tests/drivers/fuzz_lsp.js b/tests/drivers/fuzz_lsp.js
index e22a44b..f8a1d3b 100644
--- a/tests/drivers/fuzz_lsp.js
+++ b/tests/drivers/fuzz_lsp.js
@@ -1,7 +1,9 @@
 // Deterministic source/protocol fuzzing for diagnostics, caching, and recovery.
 // Usage: node tests/drivers/fuzz_lsp.js path/to/zclsp
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const { spawnSync } = require('child_process');
-const server = process.argv[2] || 'bin/zclsp';
+const server = process.argv[2] || 'build/bin/zclsp';
 let state = 0x5a17;
 function next() { state = (Math.imul(state, 1664525) + 1013904223) >>> 0; return state; }
 function frame(m) {
@@ -35,7 +37,7 @@ for (let i = 0; i < 32; i++) {
 	msgs.push({ jsonrpc: '2.0', method: 'textDocument/didChange', params: { textDocument: { uri, version: 2 }, contentChanges: [{ text: fixed }] } });
 }
 const stdUri = 'file:///fuzz-std.zc';
-msgs.push({ jsonrpc: '2.0', method: 'textDocument/didOpen', params: { textDocument: { uri: stdUri, languageId: 'zc', version: 1, text: 'include std;\nfn main() { return Text.starts("alpha", "al"); }\n' } } });
+msgs.push({ jsonrpc: '2.0', method: 'textDocument/didOpen', params: { textDocument: { uri: stdUri, languageId: 'zc', version: 1, text: 'include std;\nfn main() { return std.Text.starts("alpha", "al"); }\n' } } });
 
 // Keep one server alive while documents are repeatedly opened, made malformed,
 // repaired, closed, and reopened at a new version. This exercises cache
@@ -57,7 +59,7 @@ for (const [uri, text] of churn) {
 	msgs.push({ jsonrpc: '2.0', method: 'textDocument/didOpen', params: { textDocument: { uri, languageId: 'zc', version: churnVersion++, text } } });
 }
 msgs.push({ jsonrpc: '2.0', method: 'exit' });
-const run = spawnSync(server, [], { input: Buffer.concat(msgs.map(frame)), timeout: 60000, maxBuffer: 1 << 28 });
+const run = spawnSync(server, [], { input: Buffer.concat(msgs.map(frame)), timeout: 60000 * TIMEOUT_SCALE, maxBuffer: 1 << 28 });
 if (run.error || run.status !== 0) throw run.error || new Error(`server exit ${run.status}: ${run.stderr}`);
 const out = parse(run.stdout);
 const diagnostics = new Map();
diff --git a/tests/drivers/fuzz_malformed.py b/tests/drivers/fuzz_malformed.py
index 5bf97cf..42b8a0e 100644
--- a/tests/drivers/fuzz_malformed.py
+++ b/tests/drivers/fuzz_malformed.py
@@ -8,7 +8,7 @@ import subprocess
 import sys
 
 
-bins = sys.argv[1:] or ["bin/zy", "bin/zym"]
+bins = sys.argv[1:] or ["build/bin/zy", "build/bin/zym"]
 if len(bins) == 1:
     bins.append(bins[0])
 rng = random.Random(0xC0DE)
diff --git a/tests/drivers/fuzz_wasm.js b/tests/drivers/fuzz_wasm.js
index b0982d4..22fa7d5 100644
--- a/tests/drivers/fuzz_wasm.js
+++ b/tests/drivers/fuzz_wasm.js
@@ -31,7 +31,7 @@ function quote(s) { return '"' + s + '"'; }
 	lines.push(' churn(300); gc(); put_n(live_objects() - base); put_c(32);', ' put_n(stable()); put_c(10);', ' return 0;', '}');
 	expected.push(0, 73);
 	const source = lines.join('\n') + '\n', want = expected.join(' ') + '\n';
-	const zc = await ZC.load(fs.readFileSync(process.argv[2] || 'src/web/zc.wasm'));
+	const zc = await ZC.load(fs.readFileSync(process.argv[2] || 'build/web/zc.wasm'));
 	const result = await zc.run(source);
 	if (result.output !== want) throw new Error(`wasm fuzz mismatch\nexpected: ${want.slice(0, 180)}\nactual: ${result.output.slice(0, 180)}\nmessages: ${result.messages}`);
 	console.log('ok   wasm compiler/runtime/stdlib fuzz: 128 expressions, 300 scoped allocations and GC, and 32 Text/Bytes cases');
diff --git a/tests/drivers/genome_blob_test.py b/tests/drivers/genome_blob_test.py
index 81533a7..fea055b 100644
--- a/tests/drivers/genome_blob_test.py
+++ b/tests/drivers/genome_blob_test.py
@@ -1,13 +1,17 @@
 #!/usr/bin/env python3
 # documentation precedes the symbol table; the boot header must skip those bytes.
+# usage: python3 tests/drivers/genome_blob_test.py [build/lsp]   (the documented language server image)
 import pathlib
 import re
+import struct
+import sys
 
-source = pathlib.Path('src/core/genome.h').read_text()
-org = int(re.search(r'#define GORG (\d+)', source)[1])
-length = int(re.search(r'#define GLEN (\d+)', source)[1])
-words = [int(word.strip()) for word in re.search(r'genome\[\]\s*=\s*\{([\s\S]*?)\};', source)[1].split(',') if word.strip()]
-assert len(words) == length and words[6] == org + length
+folder = pathlib.Path(sys.argv[1] if len(sys.argv) > 1 else 'build/lsp')
+image = (folder / 'lsp_genome.bin').read_bytes()
+org = int(re.search(r'#define GORG (?:0x)?([0-9A-Fa-f]+)', (folder / 'memmap.h').read_text())[1], 16)
+words = list(struct.unpack('<%dq' % (len(image) // 8), image))
+length = len(words)
+assert words[6] == org + length
 cursor = words[5] - org
 assert 7 <= cursor < length
 records = {}
@@ -23,8 +27,8 @@ while words[cursor]:
     cursor += 1
     records[name] = (kind, value, signature)
 assert cursor == length - 1
-assert len(records) > 1000 and records['start'][0] == 1
-assert records['reserve_code'][0] == 1 and records['build_image_grow'][0] == 1
+assert len(records) > 1000 and records['run.start'][0] == 1
+assert records['run.reserve_code'][0] == 1 and records['run.build_image'][0] == 1
 assert any(name.startswith('doc ') for name in records), 'the fixture contains documentation bytes'
 for name, (kind, value, _) in records.items():
     if kind == 8:
diff --git a/tests/drivers/hints_test.js b/tests/drivers/hints_test.js
index 8bb1934..b3598be 100644
--- a/tests/drivers/hints_test.js
+++ b/tests/drivers/hints_test.js
@@ -1,5 +1,7 @@
 // hints are informational diagnostics (severity 3) and follow positional hints on / small / off directives.
 // usage: node tests/drivers/hints_test.js path/to/zclsp
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const server = process.argv[2];
@@ -10,7 +12,7 @@ function diagnostics(text) {
         { jsonrpc: '2.0', id: 1, method: 'initialize', params: {} },
         { jsonrpc: '2.0', method: 'textDocument/didOpen', params: { textDocument: { uri, version: 1, languageId: 'zc', text } } },
         { jsonrpc: '2.0', method: 'exit' }].map(frame));
-    const r = cp.spawnSync(server, process.argv.slice(3), { input, timeout: 20000, maxBuffer: 4 << 20 });
+    const r = cp.spawnSync(server, process.argv.slice(3), { input, timeout: 20000 * TIMEOUT_SCALE, maxBuffer: 4 << 20 });
     assert.strictEqual(r.status, 0, String(r.stderr));
     let d = r.stdout, out = [];
     while (d.length) {
diff --git a/tests/drivers/hover_features_test.js b/tests/drivers/hover_features_test.js
index d6e1226..25f5965 100644
--- a/tests/drivers/hover_features_test.js
+++ b/tests/drivers/hover_features_test.js
@@ -1,5 +1,7 @@
 // focused type, inference, and block-documentation hover regressions.
 // usage: node tests/drivers/hover_features_test.js path/to/zclsp
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const server = process.argv[2];
@@ -21,7 +23,7 @@ function hover(text, needle, nth = 0) {
         { jsonrpc: '2.0', id: 2, method: 'textDocument/hover', params: { textDocument: { uri }, position: { line, character } } },
         { jsonrpc: '2.0', method: 'exit' },
     ];
-    const result = cp.spawnSync(server, process.argv.slice(3), { input: Buffer.concat(messages.map(frame)), timeout: 10000, maxBuffer: 4 << 20 });
+    const result = cp.spawnSync(server, process.argv.slice(3), { input: Buffer.concat(messages.map(frame)), timeout: 10000 * TIMEOUT_SCALE, maxBuffer: 4 << 20 });
     assert.strictEqual(result.status, 0, String(result.stderr));
     let data = result.stdout;
     while (data.length) {
diff --git a/tests/drivers/hover_surface_test.js b/tests/drivers/hover_surface_test.js
index 13a9a3f..688aca6 100644
--- a/tests/drivers/hover_surface_test.js
+++ b/tests/drivers/hover_surface_test.js
@@ -1,4 +1,6 @@
 // hover declarations and instructions in the source-only documents opened by f12.
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const fs = require('fs');
 const cp = require('child_process');
@@ -48,7 +50,7 @@ if (process.argv[2] === '--wasm' || process.argv[2] === '--vm') {
     for (const m of messages) p.stdin.write(frame({ jsonrpc: '2.0', ...m }));
     out = Buffer.concat(chunks);
 } else {
-    const r = cp.spawnSync(process.argv[2], process.argv.slice(3), { input: Buffer.concat(messages.map(m => frame({ jsonrpc: '2.0', ...m }))), timeout: 60000, maxBuffer: 32 << 20 });
+    const r = cp.spawnSync(process.argv[2], process.argv.slice(3), { input: Buffer.concat(messages.map(m => frame({ jsonrpc: '2.0', ...m }))), timeout: 60000 * TIMEOUT_SCALE, maxBuffer: 32 << 20 });
     assert.strictEqual(r.status, 0, String(r.stderr)); out = r.stdout;
 }
 const replies = new Map();
diff --git a/tests/drivers/hover_values_test.js b/tests/drivers/hover_values_test.js
index badc2ed..0f09cfc 100644
--- a/tests/drivers/hover_values_test.js
+++ b/tests/drivers/hover_values_test.js
@@ -1,4 +1,6 @@
 // value previews follow the compiler's bindings and the position of each use.
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const server = process.argv[2];
@@ -17,7 +19,7 @@ function hover(text, needle, nth = 0) {
         const body = Buffer.from(JSON.stringify(m));
         return Buffer.concat([Buffer.from('Content-Length: ' + body.length + '\r\n\r\n'), body]);
     }));
-    const result = cp.spawnSync(server, process.argv.slice(3), { input, timeout: 20000, maxBuffer: 8 << 20 });
+    const result = cp.spawnSync(server, process.argv.slice(3), { input, timeout: 20000 * TIMEOUT_SCALE, maxBuffer: 8 << 20 });
     assert.strictEqual(result.status, 0, String(result.stderr));
     let data = result.stdout;
     while (data.length) {
diff --git a/tests/drivers/icon_test.py b/tests/drivers/icon_test.py
index 560c622..72cd69b 100644
--- a/tests/drivers/icon_test.py
+++ b/tests/drivers/icon_test.py
@@ -5,7 +5,7 @@ import argparse
 import subprocess
 
 parser = argparse.ArgumentParser()
-parser.add_argument('vm', nargs='?', default='bin/zy')
+parser.add_argument('vm', nargs='?', default='build/bin/zy')
 parser.add_argument('--case', default='')
 parser.add_argument('--js', action='store_true')
 parser.add_argument('--source', action='store_true', help='test the working library source instead of the embedded module')
diff --git a/tests/drivers/image_run.js b/tests/drivers/image_run.js
index f657916..ea05f9f 100644
--- a/tests/drivers/image_run.js
+++ b/tests/drivers/image_run.js
@@ -2,12 +2,11 @@
 const fs = require('fs');
 const { TinyVM } = require('../../build/js/tinyvm.js');
 const { mapValues } = require('../../src/js/mapvalues.js');
-const header = fs.readFileSync(process.argv[2], 'utf8');
-const org = Number(header.match(/#define\s+GORG\s+(\d+)/)[1]);
-const words = header.match(/genome\[\]\s*=\s*\{([\s\S]*?)\};/)[1].split(',').map(s => s.trim()).filter(Boolean);
+// usage: node tests/drivers/image_run.js genome.bin memmap.h [--stdin]
+const image = fs.readFileSync(process.argv[2]);
 const layout = mapValues(process.argv[3], ['GORG', 'DS0', 'DSLIM', 'RS0', 'RSLIM', 'SYSGATE', 'ZFP', 'HEAP_LO', 'HEAP_HI']);
 const machine = new TinyVM({ layout, onMessage: message => process.stderr.write(message) });
-machine.loadGenome(words, org);
+machine.loadImage(image, layout.GORG);
 if (process.argv[4] === '--stdin') machine.setInput(fs.readFileSync(0));
 const status = machine.run();
 process.stdout.write(machine.getOutput());
diff --git a/tests/drivers/imagekit.py b/tests/drivers/imagekit.py
new file mode 100644
index 0000000..6cc083f
--- /dev/null
+++ b/tests/drivers/imagekit.py
@@ -0,0 +1,34 @@
+"""shared steps for the drivers that build their own images: pick a c compiler with
+#embed, and link a microcore around a genome image (little-endian 64-bit words)
+for a given memory map. everything is written into the caller's directory."""
+import os
+import shutil
+import subprocess
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[2]
+DEFAULT_MAP = ROOT / 'build' / 'core' / 'map' / 'memmap.h'
+MICRO_SOURCES = ['src/micro/micro.c', 'src/micro/micro_port.h', 'src/micro/port_linux.c',
+                 'src/core/fops.h', 'src/core/bops.h', 'src/core/stack.h', 'src/core/genome.h']
+
+
+def compiler():
+    """the c compiler: CC, or the one src/tools/findcc.sh picks."""
+    if os.environ.get('CC'):
+        return os.environ['CC']
+    return subprocess.run(['sh', str(ROOT / 'src/tools/findcc.sh')], check=True, capture_output=True, text=True).stdout.strip()
+
+
+def micro_image(directory, image, memmap=DEFAULT_MAP, threads=True, name='image', timeout=60):
+    """link a microcore in directory that boots image (bytes). memmap is the map header the
+    image was built for. returns the executable's path."""
+    directory = Path(directory)
+    (directory / 'genome.bin').write_bytes(image)
+    shutil.copy(memmap, directory / 'memmap.h')
+    for f in MICRO_SOURCES:
+        shutil.copy(ROOT / f, directory)
+    flags = ['-pthread', '-DZY_THREADS'] if threads else []
+    out = directory / name
+    subprocess.run([compiler(), '-O2', '-w', '-fwrapv', *flags, str(directory / 'micro.c'), str(directory / 'port_linux.c'),
+                    '-I' + str(directory), '-o', str(out)], check=True, timeout=timeout)
+    return out
diff --git a/tests/drivers/layout_config_test.py b/tests/drivers/layout_config_test.py
index 469e7dd..2f0fa07 100644
--- a/tests/drivers/layout_config_test.py
+++ b/tests/drivers/layout_config_test.py
@@ -5,7 +5,7 @@ import subprocess
 import tempfile
 
 root = pathlib.Path(__file__).resolve().parents[2]
-tool = root / 'bin/genmap'
+tool = root / 'build/bin/genmap'
 result = subprocess.run([tool, '--help'], capture_output=True, text=True)
 assert result.returncode == 0 and '--generated-text' in result.stderr
 invalid = [
diff --git a/tests/drivers/lsp_growth_test.js b/tests/drivers/lsp_growth_test.js
index b06230a..6d221fd 100644
--- a/tests/drivers/lsp_growth_test.js
+++ b/tests/drivers/lsp_growth_test.js
@@ -1,5 +1,7 @@
 // focused regressions for growing document, uri, hover, and name-set storage.
 // usage: node tests/drivers/lsp_growth_test.js path/to/zclsp-or-lsp.wasm
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const { wasmProcess } = require('../../editors/vscode/client/wasmproc');
@@ -36,7 +38,7 @@ if (target.endsWith('.wasm')) {
     for (const message of messages) assert.ok(server.stdin.write(frame(message)));
     output = Buffer.concat(chunks);
 } else {
-    const result = cp.spawnSync(target, [], { input: Buffer.concat(messages.map(frame)), timeout: 30000, maxBuffer: 8 << 20 });
+    const result = cp.spawnSync(target, [], { input: Buffer.concat(messages.map(frame)), timeout: 30000 * TIMEOUT_SCALE, maxBuffer: 8 << 20 });
     assert.strictEqual(result.status, 0, String(result.stderr));
     output = result.stdout;
 }
diff --git a/tests/drivers/lsp_sandbox.js b/tests/drivers/lsp_sandbox.js
index 14bc1e3..41523cc 100644
--- a/tests/drivers/lsp_sandbox.js
+++ b/tests/drivers/lsp_sandbox.js
@@ -2,10 +2,12 @@
 // (immediate functions). the server must not let that code write files, so a file that
 // tries to leaves nothing behind and the server still answers.
 // usage: node tests/drivers/lsp_sandbox.js path/to/zclsp
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const cp = require('child_process'), fs = require('fs'), os = require('os'), path = require('path');
 const target = path.join(os.tmpdir(), 'zc-sandbox-' + process.pid);
 try { fs.unlinkSync(target); } catch (e) {}
-const src = 'immediate fn evil() { let fd = syscall(1, "' + target + '", 1, 0); syscall(4, fd, 65, 1); syscall(2, fd, 0, 0); return 0; }\nevil\nfn main() { return 0; }\n';
+const src = 'include rt, run;\nimmediate fn evil() { run.next(); let fd = rt.syscall(1, "' + target + '", 1, 0); rt.syscall(4, fd, 65, 1); rt.syscall(2, fd, 0, 0); return 0; }\nevil\nfn main() { return 0; }\n';
 const frame = m => { const b = Buffer.from(JSON.stringify(m)); return Buffer.concat([Buffer.from('Content-Length: ' + b.length + '\r\n\r\n'), b]); };
 const input = Buffer.concat([
 	frame({ jsonrpc: '2.0', id: 1, method: 'initialize', params: { processId: 1, capabilities: {} } }),
@@ -13,7 +15,7 @@ const input = Buffer.concat([
 	frame({ jsonrpc: '2.0', id: 3, method: 'textDocument/semanticTokens/full', params: { textDocument: { uri: 'file:///evil.zc' } } }),
 	frame({ jsonrpc: '2.0', method: 'exit' }),
 ]);
-const r = cp.spawnSync(process.argv[2], [], { input, timeout: 20000 });
+const r = cp.spawnSync(process.argv[2], [], { input, timeout: 20000 * TIMEOUT_SCALE });
 const wrote = fs.existsSync(target);
 if (wrote) fs.unlinkSync(target);
 const answered = r.stdout && r.stdout.includes('"id":3');
diff --git a/tests/drivers/lsp_test.js b/tests/drivers/lsp_test.js
index ab43c41..18d8bf7 100644
--- a/tests/drivers/lsp_test.js
+++ b/tests/drivers/lsp_test.js
@@ -1,5 +1,7 @@
 // protocol tests for the language server (node, no packages).
 // usage: node tests/drivers/lsp_test.js path/to/zclsp
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const { spawnSync } = require('child_process');
 const fs = require('fs');
 const server = process.argv[2];
@@ -24,7 +26,7 @@ function parse(buf) {
 	return out;
 }
 function run(msgs) {
-	const r = spawnSync(server, [], { input: Buffer.concat(msgs.map(frame)), timeout: 30000, maxBuffer: 1 << 28 });
+	const r = spawnSync(server, [], { input: Buffer.concat(msgs.map(frame)), timeout: 30000 * TIMEOUT_SCALE, maxBuffer: 1 << 28 });
 	return { code: r.status, msgs: parse(r.stdout) };
 }
 const init = id => ({ jsonrpc: '2.0', id, method: 'initialize', params: {} });
@@ -173,7 +175,7 @@ check(hv && hv.includes('leaves the function with a value'), 'a keyword shows wh
 const builtinSource = 'include rt; fn main() {\n\trt.put_c(32);\n\treturn 0;\n}\n';
 hv = hover(builtinSource, 1, at(builtinSource, 1, 'put_c'));
 check(hv && hv.includes('put_c('), 'a built-in function shows its signature', hv);
-const kwsrc = 'include rt; fn main() {\n\tint* p = new(int);\n\trt.free(p);\n\treturn 0;\n}\n';
+const kwsrc = 'include rt; fn main() {\n\tint* p = rt.new(int);\n\trt.free(p);\n\treturn 0;\n}\n';
 hv = hover(kwsrc, 1, at(kwsrc, 1, 'new'));
 check(hv && hv.includes('new(T)') && hv.includes('fresh heap object') && hv.includes('owns it'), 'hover on new shows its form and ownership behavior', hv);
 hv = hover(kwsrc, 2, at(kwsrc, 2, 'free'));
@@ -209,7 +211,7 @@ check(r.code === 0 && r.msgs.some(m => m.id === 9 && m.result === null), 'shutdo
 
 // the corpus: every valid program checks clean, every bad one is rejected with its message
 function cli(file) {
-	const r = spawnSync(server, [], { input: fs.readFileSync(file), timeout: 30000 });
+	const r = spawnSync(server, [], { input: fs.readFileSync(file), timeout: 30000 * TIMEOUT_SCALE });
 	return r.stdout.toString();
 }
 let clean = 0, dirty = [];
diff --git a/tests/drivers/memory_limits_test.py b/tests/drivers/memory_limits_test.py
index a973480..808a239 100644
--- a/tests/drivers/memory_limits_test.py
+++ b/tests/drivers/memory_limits_test.py
@@ -13,7 +13,7 @@ source = '''fn main() {
  return 0;
 }
 '''
-commands = [['bin/zy'], ['bin/zym'], ['node', 'src/js/tinyvm.js']]
+commands = [['build/bin/zy'], ['build/bin/zym'], ['node', 'src/js/tinyvm.js']]
 environment = dict(os.environ, TINYVM_MAX_MEMORY_WORDS='16777216')
 for command in commands:
     result = subprocess.run(command, input=source, text=True, capture_output=True, env=environment, timeout=15)
diff --git a/tests/drivers/nav_test.js b/tests/drivers/nav_test.js
index 23afbf8..8f0d8fd 100644
--- a/tests/drivers/nav_test.js
+++ b/tests/drivers/nav_test.js
@@ -1,5 +1,7 @@
 // go to definition and find references, in the document and across includes.
 // usage: node tests/drivers/nav_test.js path/to/zclsp   (run from the repository root)
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const fs = require('fs');
@@ -18,7 +20,7 @@ function request(text, needle, method, extra = {}) {
         { jsonrpc: '2.0', method: 'textDocument/didOpen', params: { textDocument: { uri, version: 1, languageId: 'zc', text } } },
         { jsonrpc: '2.0', id: 2, method, params: { textDocument: { uri }, position, ...extra } },
         { jsonrpc: '2.0', method: 'exit' }].map(frame));
-    const r = cp.spawnSync(server, process.argv.slice(3), { input, cwd: root, timeout: 30000, maxBuffer: 8 << 20 });
+    const r = cp.spawnSync(server, process.argv.slice(3), { input, cwd: root, timeout: 30000 * TIMEOUT_SCALE, maxBuffer: 8 << 20 });
     assert.strictEqual(r.status, 0, String(r.stderr));
     let d = r.stdout, init;
     while (d.length) {
diff --git a/tests/drivers/protocol_growth_test.js b/tests/drivers/protocol_growth_test.js
index 64015d8..d8dff6c 100644
--- a/tests/drivers/protocol_growth_test.js
+++ b/tests/drivers/protocol_growth_test.js
@@ -1,4 +1,6 @@
 // preserve long request identifiers and ignore deeply nested unknown json fields.
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const target = process.argv[2];
@@ -15,7 +17,7 @@ for (let i = 0; i < 24; i++) messages.push({ jsonrpc: '2.0', method: 'textDocume
     text: 'enum choice { item { int value; }, empty };\nfn main() { choice*.m p = choice.item(7); return p.item_value; }\n',
 } } });
 messages.push({ jsonrpc: '2.0', id: 'finish', method: 'shutdown', params: null }, { jsonrpc: '2.0', method: 'exit' });
-const result = cp.spawnSync(target, [], { input: Buffer.concat(messages.map(frame)), timeout: 20000, maxBuffer: 8 << 20 });
+const result = cp.spawnSync(target, [], { input: Buffer.concat(messages.map(frame)), timeout: 20000 * TIMEOUT_SCALE, maxBuffer: 8 << 20 });
 assert.strictEqual(result.status, 0, String(result.stderr));
 const responses = [];
 let data = result.stdout;
diff --git a/tests/drivers/runtime_image_test.py b/tests/drivers/runtime_image_test.py
index c1f4b9c..d214613 100644
--- a/tests/drivers/runtime_image_test.py
+++ b/tests/drivers/runtime_image_test.py
@@ -1,14 +1,18 @@
 #!/usr/bin/env python3
 """self-hosted run-only images retain enhancements and generic method bodies."""
+import sys
 import argparse
 import subprocess
 import tempfile
 from pathlib import Path
+sys.dont_write_bytecode = True  # importing imagekit must not leave __pycache__ in the tree
+from imagekit import micro_image
 
 parser = argparse.ArgumentParser()
 parser.add_argument('--case', default='')
-parser.add_argument('--host', default='bin/zy')
-parser.add_argument('--mkgenome', default='bin/mkgenome')
+parser.add_argument('--host', default='build/bin/zy')
+parser.add_argument('--mkgenome', default='build/bin/mkgenome')
+parser.add_argument('--map', default='build/core/map/memmap.h')
 args = parser.parse_args()
 cases = [
     ('enhancements', 'include rt; fn main() { rt.put_n(17 % 5); rt.put_c(32); rt.put_n(17 / 5); }', b'2 3'),
@@ -23,12 +27,9 @@ for name, source, expected in cases:
         directory = Path(work)
         r = subprocess.run([args.host], input=Path('src/tools/build.zc').read_bytes() + b'`' + prefix + source.encode(), capture_output=True, timeout=30)
         assert r.returncode == 0 and len(r.stdout) >= 56 and not r.stdout.startswith(b'zc:'), (name, r.stdout[:1000], r.stderr)
-        header = subprocess.run([args.mkgenome], input=r.stdout, capture_output=True, timeout=5)
-        assert header.returncode == 0, (name, header.stderr)
-        (directory / 'genome.h').write_bytes(header.stdout)
-        for f in ['src/core/memmap.h', 'src/core/fops.h', 'src/core/bops.h', 'src/core/stack.h', 'src/micro/micro.c', 'src/micro/micro_port.h', 'src/micro/port_linux.c']:
-            (directory / Path(f).name).write_bytes(Path(f).read_bytes())
-        subprocess.run(['cc', '-O2', '-w', '-fwrapv', '-pthread', '-DZY_THREADS', str(directory / 'micro.c'), str(directory / 'port_linux.c'), '-I' + work, '-o', str(directory / 'image')], check=True, timeout=30)
-        r = subprocess.run([str(directory / 'image')], capture_output=True, timeout=10)
+        image = subprocess.run([args.mkgenome], input=r.stdout, capture_output=True, timeout=5)
+        assert image.returncode == 0, (name, image.stderr)
+        binary = micro_image(directory, image.stdout, args.map)
+        r = subprocess.run([str(binary)], capture_output=True, timeout=10)
         assert r.returncode == 0 and r.stdout == expected, (name, r.returncode, r.stdout, r.stderr, expected)
         print('ok   self-hosted run-only image: ' + name)
diff --git a/tests/drivers/seed_growth_test.py b/tests/drivers/seed_growth_test.py
index 426c970..b94445e 100644
--- a/tests/drivers/seed_growth_test.py
+++ b/tests/drivers/seed_growth_test.py
@@ -1,25 +1,24 @@
 #!/usr/bin/env python3
 # stage 0 accepts long source streams and grows a tiny initial image reservation.
+import sys
 import pathlib
 import subprocess
 import tempfile
+sys.dont_write_bytecode = True  # importing imagekit must not leave __pycache__ in the tree
+from imagekit import compiler, micro_image
 
 root = pathlib.Path(__file__).resolve().parents[2]
+(root / 'build').mkdir(exist_ok=True)
 with tempfile.TemporaryDirectory(prefix='seed-growth-', dir=root / 'build') as directory:
     folder = pathlib.Path(directory)
-    subprocess.run(['bin/genmap', '--preset', 'run', '--grow', '--genome', '600000', '--heap', '1048576', '-o', directory], check=True, capture_output=True)
-    compiler = folder / 'zc0'
-    subprocess.run(['cc', '-O1', '-w', '-fwrapv', '-DMAXW=16', 'src/tools/zc0.c', '-I' + directory, '-Isrc/core', '-o', str(compiler)], check=True)
+    subprocess.run(['build/bin/genmap', '--preset', 'run', '--grow', '--genome', '600000', '--heap', '1048576', '-o', directory], check=True, capture_output=True)
+    zc0 = folder / 'zc0'
+    subprocess.run([compiler(), '-O1', '-w', '-fwrapv', '-DMAXW=16', 'src/tools/zc0.c', '-I' + directory, '-Isrc/core', '-o', str(zc0)], check=True)
     source = '/*' + 'x' * (5 << 20) + '*/\n'
-    source += (folder / 'rt.zc').read_text() + (root / 'src/runtime/run.zc').read_text()
-    source += 'let data[550000]; fn main() { data[549999] = 7; put_n(data[549999]); put_c(32); put_n(4611686018427387904); put_c(10); return 0; }\n'
-    with (folder / 'genome.h').open('w') as output:
-        subprocess.run([str(compiler)], input=source, text=True, stdout=output, check=True, timeout=30)
-    binary = folder / 'vm'
-    import shutil
-    for path in ['src/micro/micro.c', 'src/micro/micro_port.h', 'src/micro/port_linux.c', 'src/core/fops.h', 'src/core/bops.h', 'src/core/stack.h']:
-        shutil.copy(root / path, folder)
-    subprocess.run(['cc', '-O2', '-w', '-fwrapv', str(folder / 'micro.c'), str(folder / 'port_linux.c'), '-I' + directory, '-o', str(binary)], check=True)
+    source += (folder / 'rt.zc').read_text() + (root / 'src/core/core.zc').read_text() + (root / 'src/runtime/run.zc').read_text()
+    source += 'namespace; include rt; let data[550000]; fn main() { data[549999] = 7; rt.put_n(data[549999]); rt.put_c(32); rt.put_n(4611686018427387904); rt.put_c(10); return 0; }\n'
+    image = subprocess.run([str(zc0)], input=source.encode(), capture_output=True, check=True, timeout=30).stdout
+    binary = micro_image(folder / 'vm', image, folder / 'memmap.h', threads=False) if (folder / 'vm').mkdir() is None else None
     result = subprocess.run([str(binary)], text=True, capture_output=True, timeout=20)
     assert result.returncode == 0 and result.stdout == '7 4611686018427387904\n', (result.returncode, result.stdout, result.stderr)
 print('ok   stage 0 reads beyond four megabytes and grows beyond its initial image capacity')
diff --git a/tests/drivers/stack_growth_test.py b/tests/drivers/stack_growth_test.py
index d4abe81..3c90305 100644
--- a/tests/drivers/stack_growth_test.py
+++ b/tests/drivers/stack_growth_test.py
@@ -4,6 +4,8 @@ import subprocess
 import sys
 import tempfile
 from pathlib import Path
+sys.dont_write_bytecode = True  # importing imagekit must not leave __pycache__ in the tree
+from imagekit import compiler
 
 command = sys.argv[1:]
 
@@ -12,47 +14,53 @@ def run(source, expected, compile_image=False):
     if compile_image and command[0] == 'node':
         # compile the execution stress cases once with stage 0, so a javascript
         # compiler's speed does not determine the execution-test timeout.
+        Path('build').mkdir(exist_ok=True)
         with tempfile.TemporaryDirectory(prefix='stack-image-', dir='build') as directory:
             target = Path(directory)
-            subprocess.run(['bin/genmap', '--preset', 'run', '--grow', '--heap', '1048576', '--genome', '131072', '--frame', '4096', '--return', '256', '--data', '3072', '-o', directory], check=True, capture_output=True)
-            compiler = target / 'zc0'
-            subprocess.run(['cc', '-O1', '-w', '-fwrapv', 'src/tools/zc0.c', '-I' + directory, '-Isrc/core', '-o', str(compiler)], check=True, capture_output=True)
-            full_source = (target / 'rt.zc').read_text() + Path('src/runtime/run.zc').read_text() + source
-            image = subprocess.run([str(compiler)], input=full_source, text=True, capture_output=True, check=True)
-            header = target / 'genome.h'
-            header.write_text(image.stdout)
-            result = subprocess.run(['node', 'tests/drivers/image_run.js', str(header), str(target / 'memmap.h')], text=True, capture_output=True, timeout=45)
+            subprocess.run(['build/bin/genmap', '--preset', 'run', '--grow', '--heap', '1048576', '--genome', '131072', '--frame', '4096', '--return', '256', '--data', '3072', '-o', directory], check=True, capture_output=True)
+            zc0 = target / 'zc0'
+            subprocess.run([compiler(), '-O1', '-w', '-fwrapv', 'src/tools/zc0.c', '-I' + directory, '-Isrc/core', '-o', str(zc0)], check=True, capture_output=True)
+            full_source = (target / 'rt.zc').read_text() + Path('src/core/core.zc').read_text() + Path('src/runtime/run.zc').read_text() + source
+            image = subprocess.run([str(zc0)], input=full_source.encode(), capture_output=True, check=True)
+            (target / 'genome.bin').write_bytes(image.stdout)
+            result = subprocess.run(['node', 'tests/drivers/image_run.js', str(target / 'genome.bin'), str(target / 'memmap.h')], text=True, capture_output=True, timeout=45)
     else:
         result = subprocess.run(command, input=source, text=True, capture_output=True, timeout=45)
     assert result.returncode == 0 and result.stdout == expected, (command, result.returncode, result.stdout, result.stderr)
 
 
-run('''fn main() {
- int old_data = data_top - data_low, old_return = return_top - return_low;
- put_n(reserve_data(old_data + 1) > old_data); put_c(32);
- put_n(reserve_returns(old_return + 1) > old_return); put_c(32);
- gc(); put_n(data_node != 0 && return_node != 0); put_c(10); return 0;
+run('''namespace;
+include rt;
+fn main() {
+ int old_data = rt.data_top - rt.data_low, old_return = rt.return_top - rt.return_low;
+ rt.put_n(rt.reserve_data(old_data + 1) > old_data); rt.put_c(32);
+ rt.put_n(rt.reserve_returns(old_return + 1) > old_return); rt.put_c(32);
+ rt.gc(); rt.put_n(rt.data_node != 0 && rt.return_node != 0); rt.put_c(10); return 0;
 }
 ''', '1 1 1\n')
 
-run('''fn main() {
- put_n(reserve_data(-1) == -1); put_c(32); put_n(reserve_returns(-1) == -1); put_c(32);
- put_n(syscall(9, 6, 0, 0) == -1); put_c(32);
- int current = syscall(9, 0, 0, 0); syscall(9, 5, current, 0);
- put_n(reserve_data(0x10000000) == -1); put_c(32); gc(); put_n(7); put_c(10); return 0;
+run('''namespace;
+include rt;
+fn main() {
+ rt.put_n(rt.reserve_data(-1) == -1); rt.put_c(32); rt.put_n(rt.reserve_returns(-1) == -1); rt.put_c(32);
+ rt.put_n(rt.syscall(9, 6, 0, 0) == -1); rt.put_c(32);
+ int current = rt.syscall(9, 0, 0, 0); rt.syscall(9, 5, current, 0);
+ rt.put_n(rt.reserve_data(0x10000000) == -1); rt.put_c(32); rt.gc(); rt.put_n(7); rt.put_c(10); return 0;
 }
 ''', '1 1 1 1 7\n')
 
 count = 40000
-source = 'fn main() { int total = asm { ' + ' '.join(str(i + 1) for i in range(count))
-source += ' + ' * (count - 1) + ' }; gc(); put_n(total); put_c(32); '
-source += 'put_n(data_node != 0); put_c(10); return 0; }\n'
+source = 'namespace; include rt; fn main() { int total = asm { ' + ' '.join(str(i + 1) for i in range(count))
+source += ' + ' * (count - 1) + ' }; rt.gc(); rt.put_n(total); rt.put_c(32); '
+source += 'rt.put_n(rt.data_node != 0); rt.put_c(10); return 0; }\n'
 run(source, '800020000 1\n', compile_image=True)
 
-run('''unchecked int descend(int n) {
- if (!n) { gc(); return 7; }
+run('''namespace;
+include rt;
+unchecked int descend(int n) {
+ if (!n) { rt.gc(); return 7; }
  return descend(n - 1) + 1;
 }
-fn main() { put_n(descend(70000)); put_c(32); put_n(return_node != 0); put_c(10); return 0; }
+fn main() { rt.put_n(descend(70000)); rt.put_c(32); rt.put_n(rt.return_node != 0); rt.put_c(10); return 0; }
 ''', '70007 1\n', compile_image=True)
 print('ok   explicit reservation, 40000 operands, and 70000 return addresses: ' + command[0])
diff --git a/tests/drivers/storage_analysis_test.js b/tests/drivers/storage_analysis_test.js
index 774fa89..704a844 100644
--- a/tests/drivers/storage_analysis_test.js
+++ b/tests/drivers/storage_analysis_test.js
@@ -1,8 +1,12 @@
 // definite storage findings use the compiler's parser and the editor protocol.
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const server = process.argv[2];
 function check(text, needle) {
+    // the runtime is an explicit import; it shares the first line so line numbers stay as written
+    text = 'include rt; ' + text;
     const uri = 'file:///storage-analysis.zc';
     const messages = [{ jsonrpc: '2.0', id: 1, method: 'initialize', params: {} },
         { jsonrpc: '2.0', method: 'textDocument/didOpen', params: { textDocument: { uri, version: 1, text } } }];
@@ -13,7 +17,7 @@ function check(text, needle) {
     }
     messages.push({ jsonrpc: '2.0', method: 'exit' });
     const input = Buffer.concat(messages.map(m => { const b = Buffer.from(JSON.stringify(m)); return Buffer.concat([Buffer.from('Content-Length: ' + b.length + '\r\n\r\n'), b]); }));
-    const r = cp.spawnSync(server, process.argv.slice(3), { input, timeout: 20000, maxBuffer: 8 << 20 });
+    const r = cp.spawnSync(server, process.argv.slice(3), { input, timeout: 20000 * TIMEOUT_SCALE, maxBuffer: 8 << 20 });
     assert.strictEqual(r.status, 0, String(r.stderr));
     const replies = []; let data = r.stdout;
     while (data.length) {
@@ -27,50 +31,50 @@ function check(text, needle) {
 }
 const prefix = 'unchecked fn main() {\n';
 for (const [type, length] of [['int', 3], ['u8', 3], ['fixed int[?]', 3], ['u8[?]', 3]]) {
-    const r = check(prefix + ` let p = new(${type}, ${length});\n let alias = p;\n return alias[${length}];\n}\n`, 'alias[');
+    const r = check(prefix + ` let p = rt.new(${type}, ${length});\n let alias = p;\n return alias[${length}];\n}\n`, 'alias[');
     assert.strictEqual(r.warnings.length, 1, JSON.stringify(r.diagnostics));
     assert.match(r.warnings[0].message, /out-of-bounds.*index 3.*length 3/);
     assert.match(r.hover, /size: 3 elements.*lifetime: heap storage; live here/);
     assert.strictEqual(r.warnings[0].range.start.line, 3);
 }
-const negative = check(prefix + ' let p = new(3); return p[-1];\n}\n');
+const negative = check(prefix + ' let p = rt.new(3); return p[-1];\n}\n');
 assert.match(negative.warnings[0]?.message || '', /index -1.*length 3/);
-const freed = check(prefix + ' let p = new(int, 3);\n let q = p;\n free(p);\n return q[0];\n}\n', 'q[');
+const freed = check(prefix + ' let p = rt.new(int, 3);\n let q = p;\n rt.free(p);\n return q[0];\n}\n', 'q[');
 assert.strictEqual(freed.warnings.length, 1, JSON.stringify(freed.diagnostics));
 assert.match(freed.warnings[0].message, /use after free.*line 4/);
 assert.match(freed.hover, /size: 3 elements.*lifetime: ended on line 4/);
-const dereference = check(prefix + ' let p = new(int); free(p); return *p;\n}\n');
+const dereference = check(prefix + ' let p = rt.new(int); rt.free(p); return *p;\n}\n');
 assert.match(dereference.warnings[0]?.message || '', /use after free/);
-const field = check('struct item { int value; };\n' + prefix + ' let p = new(item); free(p); return p.value;\n}\n');
+const field = check('struct item { int value; };\n' + prefix + ' let p = rt.new(item); rt.free(p); return p.value;\n}\n');
 assert.match(field.warnings[0]?.message || '', /use after free/);
 const scope = check(prefix + ' int* p;\n { let a[3]; p = a; }\n return p[0];\n}\n', 'p[');
 assert.match(scope.warnings[0]?.message || '', /use after free.*line 3/);
 assert.match(scope.hover, /lifetime: ended on line 3/);
 const safe = [
- prefix + ' let p = new(int, 3); let q = p as u8*; return q[23]; }',
- prefix + ' let p = new(int, 3); let q = (u8*)p; return q[23]; }',
+ prefix + ' let p = rt.new(int, 3); let q = p as u8*; return q[23]; }',
+ prefix + ' let p = rt.new(int, 3); let q = (u8*)p; return q[23]; }',
  prefix + ' int n = 2; let p = &n; let q = n; return q[2]; }',
- prefix + ' let p = new(int, 3); let ignored = 0 && free(p); return p[0]; }',
- prefix + ' let p = new(int, 3); let ignored = 1 || free(p); return p[0]; }',
- prefix + ' let p = new(int, 50); return p[(u8)300]; }',
- prefix + ' let p = new(int, 50); return p[300 as u8]; }',
- prefix + ' let p = new(int, 3); let q = p; q[2] = 7; free(p); return 0; }',
- prefix + ' let p = new(3); free(p); p = new(3); return p[0]; }',
- 'unchecked fn unknown(int* p) {}\n' + prefix + ' let p = new(int, 3); unknown(p); return p[9]; }',
- 'fn maybe(int n) { return n; }\n' + prefix + ' let p = new(int, 3); return p[maybe(9)]; }',
- prefix + ' let p = new(int, 3); if (1) free(p); return p[0]; }',
- prefix + ' let p = new(int, 3); while (0) free(p); return p[0]; }',
- prefix + ' let p = new(int, 3); let f = fn() { free(p); return 0; }; return p[0]; }',
- prefix + ' let p = new(int[?], 0); push(p, 9); return p[0]; }',
+ prefix + ' let p = rt.new(int, 3); let ignored = 0 && rt.free(p); return p[0]; }',
+ prefix + ' let p = rt.new(int, 3); let ignored = 1 || rt.free(p); return p[0]; }',
+ prefix + ' let p = rt.new(int, 50); return p[(u8)300]; }',
+ prefix + ' let p = rt.new(int, 50); return p[300 as u8]; }',
+ prefix + ' let p = rt.new(int, 3); let q = p; q[2] = 7; rt.free(p); return 0; }',
+ prefix + ' let p = rt.new(3); rt.free(p); p = rt.new(3); return p[0]; }',
+ 'unchecked fn unknown(int* p) {}\n' + prefix + ' let p = rt.new(int, 3); unknown(p); return p[9]; }',
+ 'fn maybe(int n) { return n; }\n' + prefix + ' let p = rt.new(int, 3); return p[maybe(9)]; }',
+ prefix + ' let p = rt.new(int, 3); if (1) rt.free(p); return p[0]; }',
+ prefix + ' let p = rt.new(int, 3); while (0) rt.free(p); return p[0]; }',
+ prefix + ' let p = rt.new(int, 3); let f = fn() { rt.free(p); return 0; }; return p[0]; }',
+ prefix + ' let p = rt.new(int[?], 0); push(p, 9); return p[0]; }',
 ];
 for (const source of safe) assert.deepStrictEqual(check(source).warnings, [], source);
-const preserved = check('int read(int* p) { return p[0]; }\n' + prefix + ' let p = new(int, 3); read(p); return p[9]; }');
+const preserved = check('int read(int* p) { return p[0]; }\n' + prefix + ' let p = rt.new(int, 3); read(p); return p[9]; }');
 assert.match(preserved.warnings[0]?.message || '', /index 9.*length 3/);
 const unknown = check('int read(int* p) { return p[0]; }\nfn main() { int n = 1; return read(&n); }\n', 'p[');
 assert.match(unknown.hover, /size: unknown.*lifetime: unknown/);
 const stack = check('fn main() { let a[3]; return a[2]; }\n', 'a[');
 assert.match(stack.hover, /size: 3 elements.*lifetime: stack storage/);
-const replacement = check('fn main() {\n let owner = new(1), replacement = new(2);\n free(owner); owner = replacement;\n return owner[0];\n}\n', 'replacement;');
+const replacement = check('fn main() {\n let owner = rt.new(1), replacement = rt.new(2);\n rt.free(owner); owner = replacement;\n return owner[0];\n}\n', 'replacement;');
 assert.ok(!replacement.diagnostics.some(d => d.severity === 1), JSON.stringify(replacement.diagnostics));
 assert.match(replacement.hover, /moved: replaces a released owner in `owner` on line 3/);
 console.log('ok   definite bounds, free and scope lifetimes, alias hovers, and conservative unknown cases');
diff --git a/tests/drivers/thread_context_test.py b/tests/drivers/thread_context_test.py
index fa3f144..b237acd 100644
--- a/tests/drivers/thread_context_test.py
+++ b/tests/drivers/thread_context_test.py
@@ -5,7 +5,7 @@ import argparse
 import subprocess
 
 parser = argparse.ArgumentParser()
-parser.add_argument('vm', nargs='?', default='bin/zy')
+parser.add_argument('vm', nargs='?', default='build/bin/zy')
 parser.add_argument('--case', default='')
 parser.add_argument('--library', default='')
 parser.add_argument('--backend', choices=('native', 'micro'), default='native')
diff --git a/tests/drivers/toolchain_lsp_contract_test.js b/tests/drivers/toolchain_lsp_contract_test.js
index 0d1b515..2872282 100644
--- a/tests/drivers/toolchain_lsp_contract_test.js
+++ b/tests/drivers/toolchain_lsp_contract_test.js
@@ -1,4 +1,6 @@
 // pending requirements have explicit protocol oracles, selectable in small groups.
+// interpreted hosts (no jit) are far slower; ZC_TEST_TIMEOUT_SCALE stretches every deadline
+const TIMEOUT_SCALE = Number(process.env.ZC_TEST_TIMEOUT_SCALE) || 1;
 const assert = require('assert');
 const cp = require('child_process');
 const fs = require('fs');
@@ -21,7 +23,7 @@ function run(text, requests = [], uri = 'file:///contracts.zc', files = []) {
         for (const message of messages) proc.stdin.write(frame(message));
         output = Buffer.concat(chunks);
     } else {
-        const r = cp.spawnSync(host, process.argv.slice(3), { input: Buffer.concat(messages.map(frame)), timeout: 60000, maxBuffer: 32 << 20 });
+        const r = cp.spawnSync(host, process.argv.slice(3), { input: Buffer.concat(messages.map(frame)), timeout: 60000 * TIMEOUT_SCALE, maxBuffer: 32 << 20 });
         assert.strictEqual(r.status, 0, String(r.stderr)); output = r.stdout;
     }
     const replies = []; let data = output;
diff --git a/tests/drivers/tools_contract_test.py b/tests/drivers/tools_contract_test.py
index df02b2b..6a98678 100644
--- a/tests/drivers/tools_contract_test.py
+++ b/tests/drivers/tools_contract_test.py
@@ -1,7 +1,6 @@
 #!/usr/bin/env python3
 """bounded accept/reject tests for standalone build tools and generated images."""
 import argparse
-import re
 import struct
 import subprocess
 import tempfile
@@ -17,32 +16,33 @@ def command(argv, data=None):
     return r
 
 if args.group == 'image':
-    source = Path('src/core/genome.h').read_text()
-    body = source.split('{', 1)[1].split('}', 1)[0]
-    words = [int(x) for x in re.findall(r'-?\d+', body)]
+    image = Path('build/core/genome.bin').read_bytes()
+    words = list(struct.unpack('<%dq' % (len(image) // 8), image))
     pack = lambda xs: b''.join(struct.pack('<q', x) for x in xs)
-    good = command(['bin/mkgenome'], pack(words))
-    assert good.returncode == 0 and f'#define GLEN {len(words)}'.encode() in good.stdout
-    for data in [b'', b'x', pack(words[:6]), pack(words) + b'x']:
-        r = command(['bin/mkgenome'], data)
-        assert r.returncode != 0 and b'incomplete' in r.stderr
+    good = command(['build/bin/mkgenome'], image)
+    assert good.returncode == 0 and good.stdout == image
+    for data in [b'', b'x', pack(words[:6]), image + b'x']:
+        r = command(['build/bin/mkgenome'], data)
+        assert r.returncode != 0 and b'incomplete' in r.stderr and not r.stdout
     for index in range(3):
         changed = words[:]; changed[index] ^= 2
-        r = command(['bin/mkgenome'], pack(changed))
-        assert r.returncode != 0 and b'not a genome' in r.stderr
-    print('ok   mkgenome roundtrip, truncation, alignment and map-header mutation contracts')
+        r = command(['build/bin/mkgenome'], pack(changed))
+        assert r.returncode != 0 and b'not a genome' in r.stderr and not r.stdout
+    r = command(['build/bin/mkgenome'], b'zc: line 1: something is wrong\nzc: 1 error\n')
+    assert r.returncode != 0 and b'something is wrong' in r.stderr and not r.stdout
+    print('ok   mkgenome roundtrip, truncation, alignment, map-header mutation and diagnostic contracts')
 elif args.group == 'map':
     for preset in ['default', 'small', 'run', 'lsp', 'fixed']:
         with tempfile.TemporaryDirectory(prefix='tinyvm preset ') as directory:
-            r = command(['bin/genmap', '--preset', preset, '-o', directory])
+            r = command(['build/bin/genmap', '--preset', preset, '-o', directory])
             assert r.returncode == 0, (preset, r.stderr)
             assert (Path(directory) / 'memmap.h').is_file()
-    assert command(['bin/genmap', '--preset', 'default', '--check']).returncode == 0
+    assert command(['build/bin/genmap', '--preset', 'default', '--check']).returncode == 0
     for options in [['--words', '-1'], ['--heap', '0'], ['--data', '0'], ['--symbols', '-1'], ['--total', '999999999999999999999'], ['--preset', 'imaginary']]:
-        r = command(['bin/genmap', *options, '--check'])
+        r = command(['build/bin/genmap', *options, '--check'])
         assert r.returncode != 0, options
     with tempfile.TemporaryDirectory(prefix='tinyvm map ') as directory:
-        r = command(['bin/genmap', '--preset', 'small', '--locals', '32', '--symbols', '64', '-o', directory])
+        r = command(['build/bin/genmap', '--preset', 'small', '--locals', '32', '--symbols', '64', '-o', directory])
         assert r.returncode == 0, r.stderr
         for name in ['memmap.h', 'rt.zc', 'compiler.zc', 'map.txt']:
             assert (Path(directory) / name).is_file(), name
@@ -50,7 +50,7 @@ elif args.group == 'map':
 else:
     r = command(['bash', '-n', 'tinyvm.sh'])
     assert r.returncode == 0, r.stderr
-    for script in ['src/tools/automap.sh', 'src/tools/mklsp.sh', 'src/tools/mklspwasm.sh', 'src/tools/mkvsix.sh', 'src/tools/embed.sh']:
+    for script in ['src/tools/automap.sh', 'src/tools/mklsp.sh', 'src/tools/mklspwasm.sh', 'src/tools/mkvsix.sh', 'src/tools/findcc.sh', 'src/tools/bootstrap-check.sh']:
         assert command(['bash', '-n', script]).returncode == 0
     assert command(['bash', 'tinyvm.sh', 'imaginary-command']).returncode != 0
     assert Path('tinyvm.bat').is_file()
diff --git a/tests/drivers/wasm_test.js b/tests/drivers/wasm_test.js
index e4f7ecb..56f32a2 100644
--- a/tests/drivers/wasm_test.js
+++ b/tests/drivers/wasm_test.js
@@ -1,9 +1,9 @@
-// runs programs on the webassembly build (src/web/zc.wasm) and compares with the expected output.
+// runs programs on the webassembly build (build/web/zc.wasm, from make web) and compares with the expected output.
 // usage: node tests/drivers/wasm_test.js [path/to/zc.wasm]
 const fs = require('fs');
 const ZC = require('../../src/web/zc.js');
 (async () => {
-	const zc = await ZC.load(fs.readFileSync(process.argv[2] || __dirname + '/../../src/web/zc.wasm'));
+	const zc = await ZC.load(fs.readFileSync(process.argv[2] || __dirname + '/../../build/web/zc.wasm'));
 	const cases = [
 		['examples/hello.zc', 'hello, world!'],
 		['examples/fact.zc', '1101110101111100000000\n3628800\n'],
diff --git a/tests/drivers/word_literals_test.py b/tests/drivers/word_literals_test.py
index a2d230d..cfac811 100644
--- a/tests/drivers/word_literals_test.py
+++ b/tests/drivers/word_literals_test.py
@@ -5,7 +5,7 @@ import subprocess
 values = [0, 1, (1 << 62) - 1, 1 << 62, (1 << 63) - 1, -(1 << 62), -(1 << 62) - 1, -(1 << 63), -1]
 source = 'fn main() {\n' + ''.join(f'put_n({value}); put_c(10);\n' for value in values) + 'return 0; }\n'
 expected = ''.join(str(value) + '\n' for value in values)
-for command in [['bin/zy'], ['bin/zym'], ['node', 'src/js/tinyvm.js']]:
+for command in [['build/bin/zy'], ['build/bin/zym'], ['node', 'src/js/tinyvm.js']]:
     result = subprocess.run(command, input=source, text=True, capture_output=True, timeout=20)
     assert result.returncode == 0 and result.stdout == expected, (command, result.stdout, result.stderr)
     print('ok   full-width positive and negative word literals: ' + command[0])
@@ -13,7 +13,7 @@ source = '''immediate fn add_word_operator() { next(); add_binop("**", 11, "4611
 add_word_operator
 fn main() { put_n(0 ** 0); put_c(10); return 0; }
 '''
-for command in [['bin/zy'], ['bin/zym'], ['node', 'src/js/tinyvm.js']]:
+for command in [['build/bin/zy'], ['build/bin/zym'], ['node', 'src/js/tinyvm.js']]:
     result = subprocess.run(command, input=source, text=True, capture_output=True, timeout=20)
     assert result.returncode == 0 and result.stdout == '4611686018427387904\n', (command, result.stdout, result.stderr)
     print('ok   full-width word in a stored operator sequence: ' + command[0])
diff --git a/tests/test.sh b/tests/test.sh
index 16aa1a9..fd2bcd3 100755
--- a/tests/test.sh
+++ b/tests/test.sh
@@ -1,9 +1,14 @@
 #!/bin/bash
 # full check: bootstraps the compiler from zc0, verifies the fixpoint, then runs
 # the examples and tests on the portable interpreter (host), the microcore, the
-# arm64 jit under qemu-user, and the llvm backend. needs gcc. the jit half
-# needs aarch64-linux-gnu-gcc and qemu-aarch64 (linux-user, not qemu-system).
-# the llvm half needs llvm-config and libLLVM. src/baremetal/run.sh boots the
+# arm64 jit under qemu-user, and the llvm backend. needs a c compiler with c23
+# #embed (src/tools/findcc.sh picks one; CC overrides it). the jit half needs
+# aarch64-linux-gnu-gcc and qemu-aarch64 (linux-user, not qemu-system).
+#
+# the suite reads nothing from build/: it lays out the default map, bootstraps
+# the compiler and builds every core into its own scratch directory, so it runs
+# the same from a clean checkout as after `make`.
+# the llvm half needs llvm-config (LLVM_CONFIG names another) and libLLVM. src/baremetal/run.sh boots the
 # microcore on qemu-system-riscv64 and qemu-system-aarch64 when those cross
 # compilers and system emulators are installed. each of these is skipped
 # when its tools are missing.
@@ -43,26 +48,36 @@ if [ -n "$SELECT" ]; then
 fi
 ROOT=$T
 
-# built here rather than inside a section: interp runs the program list on
-# it, and the run-only and bare-metal sections read it as the reference.
-gcc -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core -o $T/zy || exit 1
-gcc -O2 -w -fwrapv src/tools/genmap.c -Isrc/core -Ibuild/core -o $T/genmap || exit 1
+CC=${CC:-$(sh src/tools/findcc.sh)} || exit 1
+export CC
+# the language server runs on the interpreter unless the host has the arm64 jit, and a
+# check of a large document then takes many seconds: stretch the drivers' deadlines
+if [ -z "${ZC_TEST_TIMEOUT_SCALE:-}" ]; then case "$(uname -m)" in arm64|aarch64) ZC_TEST_TIMEOUT_SCALE=1;; *) ZC_TEST_TIMEOUT_SCALE=8;; esac; fi
+export ZC_TEST_TIMEOUT_SCALE
+# the default map, generated as make does it, and the tools built against it
+$CC -O2 -w -fwrapv src/tools/genmap.c -o $T/genmap || exit 1
+$T/genmap --preset default --check -o $T/map >$T/genmap.log 2>&1 || { cat $T/genmap.log; echo "FAIL the default map does not match the checked-in sources"; exit 1; }
+MAP=$T/map
+$CC -O1 -w -fwrapv src/tools/zc0.c -Isrc/core -I$MAP -o $T/zc0 && $CC -O1 -w -fwrapv src/tools/mkgenome.c -I$MAP -o $T/mkg || exit 1
 # the c helper for tests/programs/structval.zc: structs by value, loaded with cload
-mkdir -p build && gcc -shared -fPIC -w tests/data/sbv.c -o build/sbv.so || exit 1
+mkdir -p build && $CC -shared -fPIC -w tests/data/sbv.c -o build/sbv.so || exit 1
 
 selfc(){ (cat src/tools/build.zc; printf '`'; src) | $1 > $2; }
 
-# bootstrap: zc0 (c) -> g0, g0 compiles compiler.zc -> g1, g1 compiles it -> g2
-gcc -O1 -w -fwrapv src/tools/zc0.c -Isrc/core -Ibuild/core -o $T/zc0 && gcc -O1 -w -fwrapv src/tools/mkgenome.c -Isrc/core -Ibuild/core -o $T/mkg || exit 1
+# bootstrap: zc0 (c) -> g0, g0 compiles compiler.zc -> g1, g1 compiles it -> g2.
+# each stage's core embeds the image in its own directory
 mkdir $T/s0 $T/s1
-cp src/core/core.c src/core/io_linux.c src/core/memmap.h src/core/fops.h src/core/bops.h src/core/stack.h $T/s0/; cp src/core/core.c src/core/io_linux.c src/core/memmap.h src/core/fops.h src/core/bops.h src/core/stack.h $T/s1/
-src | $T/zc0 > $T/s0/genome.h || exit 1
-gcc -pthread -O2 -w -fwrapv -DJTYPE=int $T/s0/core.c $T/s0/io_linux.c -o $T/zy0
-selfc $T/zy0 $T/g1.bin; $T/mkg < $T/g1.bin > $T/s1/genome.h
-gcc -pthread -O2 -w -fwrapv -DJTYPE=int $T/s1/core.c $T/s1/io_linux.c -o $T/zy1
+src | $T/zc0 > $T/s0/g0.bin && $T/mkg < $T/s0/g0.bin > $T/s0/genome.bin || exit 1
+$CC -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -I$MAP --embed-dir=$T/s0 -o $T/zy0 || exit 1
+selfc $T/zy0 $T/g1.bin; $T/mkg < $T/g1.bin > $T/s1/genome.bin || exit 1
+$CC -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -I$MAP --embed-dir=$T/s1 -o $T/zy1 || exit 1
 selfc $T/zy1 $T/g2.bin
 cmp -s $T/g1.bin $T/g2.bin && chk 1 1 "fixpoint: the compiler compiles itself to the same $(($(wc -c < $T/g1.bin) / 8)) words" || chk 0 1 "fixpoint"
-cmp -s $T/s1/genome.h build/core/genome.h && chk 1 1 "genome.h is up to date" || chk 0 1 "genome.h is stale (run make genome)"
+# every core below carries the fixpoint genome: GI is the include and embed path for it
+GI="-Isrc/core -I$MAP --embed-dir=$T/s1"
+# built here rather than inside a section: interp runs the program list on
+# it, and the run-only and bare-metal sections read it as the reference.
+$CC -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c $GI -o $T/zy || exit 1
 chk "$($T/zc0 < tests/programs/zc0typed.zc | md5sum)" "$($T/zc0 < tests/programs/zc0plain.zc | md5sum)" "zc0 reads types and throws them away: typed and plain sources give one image"
 
 for n in $SECS; do
@@ -80,7 +95,7 @@ run(){	# $1 = vm command, $2 = label
 	chk "$( (cat tests/programs/backtick.zc; printf '`xyz') | $vm)" "3 3 96 39 xyz" "$l a backtick in a comment, string or char literal does not end the source"
 	chk "$($vm < examples/selfpatch.zc)" "ABC" "$l self-patching code"
 	chk "$($vm < examples/lists.zc | tr '\n' '/')" "[0 1 4 9 16 25]/live: 7/after the block: 0/" "$l ownership frees everything"
-	chk "$( (cat examples/repl.zc; printf '`fn sq(x) { return x * x; }`put_n(sq(7)); put_c(10);`put_s("hi\\n");') | $vm | tr '\n' '/')" "49/hi/" "$l repl on the resident compiler"
+	chk "$( (cat examples/repl.zc; printf '`fn sq(x) { return x * x; }`rt.put_n(sq(7)); rt.put_c(10);`rt.put_s("hi\\n");') | $vm | tr '\n' '/')" "49/hi/" "$l repl on the resident compiler"
 	chk "$($vm < examples/typed.zc | tr '\n' '/')" "last: 4/point is 2 words: x int, y int/vec<point*> is 3 words: len int, cap int, items point**/push is bool(vec<T>*, T.d)/the heap says v is a vec<point*>, and v.items[0] is a point/" "$l typed example"
 	chk "$($vm < examples/wiring.zc)" "16 1234 25 4/9" "$l enhancement example"
 	chk "$($vm < tests/programs/allocfast.zc)" "0 0 499500 0" "$l constant-size allocation fast path"
@@ -111,7 +126,7 @@ run(){	# $1 = vm command, $2 = label
 	chk "$($vm < tests/programs/enumscope.zc)" "0 5 6 blue" "$l enum members are reached as Enum.MEMBER, also in a case"
 	chk "$($vm < tests/programs/enumtype.zc)" "6 5 1" "$l typed enums: members take their enum, an enum becomes an int"
 	chk "$($vm < tests/programs/tagenum.zc)" "27 20 0 0 1 2" "$l tagged enums: members carry fields, constructors build them, a case binds the fields"
-	chk "$($vm < tests/programs/tagenum_warn.zc)" "$(printf 'zc: line 5: warning: this switch doesn'"'"'t cover rect\n0')" "$l a switch on a tagged enum that misses a member warns, on the switch's line"
+	chk "$($vm < tests/programs/tagenum_warn.zc)" "$(printf 'zc: line 8: warning: this switch doesn'"'"'t cover rect\n0')" "$l a switch on a tagged enum that misses a member warns, on the switch's line"
 	chk "$($vm < tests/programs/tagenum_two.zc)" "3 8 12" "$l two tagged enums with the same member name, and a case in an o3 loop"
 	chk "$($vm < tests/programs/o3push.zc | md5sum)" "$(md5sum < tests/programs/o3push.expected)" "$l push and pop of a growable array are inline in o3"
 	chk "$($vm < tests/programs/o3copy.zc)" "520507 1005" "$l o3 copies of a loop variable read the source instead"
@@ -136,11 +151,11 @@ hello world!42
 1
 0" "$l capture.start() collects output and end() hands back the string"
 	chk "$($vm < tests/programs/sys.zc)" "2 zy time" "$l syscalls: write, read, time"
-	chk "$($vm < tests/programs/memleak.zc)" $'leak: line 5 3 words\n1' "$l memdebug names a live allocation"
-	chk "$($vm < tests/programs/uaf.zc)" $'zc: line 7: warning: use after free: this storage\'s lifetime ended on line 6\nzy: use after free from line 4' "$l memdebug: use after free"
-	chk "$($vm < tests/programs/uaf_in.zc)" "zy: use after free from line 4" "$l memdebug: use after free through an interior pointer"
-	chk "$($vm < tests/programs/doublefree.zc)" $'zy: double free from line 4\nok' "$l memdebug: double free is reported and does nothing"
-	chk "$($vm < tests/programs/scrub.zc)" $'zc: line 6: warning: use after free: this storage\'s lifetime ended on line 5\n57005' "$l memdebug scrub poisons a freed payload"
+	chk "$($vm < tests/programs/memleak.zc)" $'leak: line 8 3 words\n1' "$l memdebug names a live allocation"
+	chk "$($vm < tests/programs/uaf.zc)" $'zc: line 10: warning: use after free: this storage\'s lifetime ended on line 9\nzy: use after free from line 7' "$l memdebug: use after free"
+	chk "$($vm < tests/programs/uaf_in.zc)" "zy: use after free from line 7" "$l memdebug: use after free through an interior pointer"
+	chk "$($vm < tests/programs/doublefree.zc)" $'zy: double free from line 7\nok' "$l memdebug: double free is reported and does nothing"
+	chk "$($vm < tests/programs/scrub.zc)" $'zc: line 9: warning: use after free: this storage\'s lifetime ended on line 8\n57005' "$l memdebug scrub poisons a freed payload"
 	chk "$($vm < tests/programs/interior.zc)" "0" "$l an interior pointer keeps a quarantined block"
 	chk "$($vm < tests/programs/wide.zc)" "1099511627776 1 1 1 -1" "$l 64-bit shifts and equality"
 	chk "$($vm < tests/programs/float.zc)" "4.000000 4.500000 3.000000 2.500000 2.500000 0.001500 0.100000 -0.125000 inf -inf nan 1 1 1 0 0 3 -3 3.000000 -2.000000 2" "$l floating point"
@@ -169,7 +184,7 @@ ABC" "$l o3 lifts byte loads and stores"
 	chk "$($vm < examples/bf.zc 2>&1 | md5sum | cut -c1-32)" "223570983752b17f7ece32e93d5e19e4" "$l example: brainfuck compiled at runtime"
 	chk "$($vm < examples/dump.zc 2>&1 | md5sum | cut -c1-32)" "757774b00f6b3cd0bfbcba66448a8619" "$l example: struct printer through reflection"
 	chk "$($vm < examples/tree.zc 2>&1 | md5sum | cut -c1-32)" "b86a2e4e9e31acc294a4ddf86be863f2" "$l example: owning tree frees itself"
-	chk "$($vm < examples/lang.zc 2>&1 | md5sum | cut -c1-32)" "6b234dc8a0a1aa0fb02eb55a6ff7ccc0" "$l example: pipe operator, unless, assert, times"
+	chk "$($vm < examples/lang.zc 2>&1 | md5sum | cut -c1-32)" "$(printf '22\none isn'"'"'t bigger than two\n***\nassertion failed on line 50\n' | md5sum | cut -c1-32)" "$l example: pipe operator, unless, assert, times"
 	chk "$($vm < examples/staged.zc 2>&1 | md5sum | cut -c1-32)" "6f790a125c48b0cc7a897cee73ee5627" "$l example: staged code compiled while running"
 	chk "$($vm < examples/quine.zc 2>&1 | md5sum | cut -c1-32)" "$(md5sum < examples/quine.zc | cut -c1-32)" "$l example: quine"
 	chk "$($vm < examples/primes.zc 2>&1 | md5sum | cut -c1-32)" "814faffc70dad0ae520c0671c33e73d4" "$l example: o3 prime sieve"
@@ -200,7 +215,7 @@ ABC" "$l o3 lifts byte loads and stores"
 }
 s_interp() {
 	T=$ROOT/interp
-	gcc -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core -o $T/zy
+	$CC -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c $GI -o $T/zy
 	run $T/zy "interp"
 	python3 tests/drivers/array_methods_test.py $T/zy > $T/arrays.out 2>&1; r=$?
 	grep -v '^ok' $T/arrays.out
@@ -218,14 +233,14 @@ s_interp() {
 	chk "$($T/zy < tests/programs/infer_return.zc)" "3" "an owned return with no .u is inferred from the body"
 	chk "$($T/zy < tests/programs/discard_m.zc)" "7" "m* discards an unnamed u result"
 	chk "$($T/zy < tests/programs/closure.zc | tr '\n' ' ')" "31 35 42 2 7 7 109 30 7 16 33 20 101 " "closures: calls through values, captures, nesting, returns"
-	chk "$($T/zy < tests/programs/decl_undefined.zc 2>&1 | head -1)" "zc: line 1: helper is used but never defined" "a declared function nothing defines fails a build"
+	chk "$($T/zy < tests/programs/decl_undefined.zc 2>&1 | head -1)" "zc: line 3: helper is used but never defined" "a declared function nothing defines fails a build"
 	if [ "$(uname -s)" = Linux ]; then chk "$($T/zy < tests/programs/rawsys.zc)" "-38" "Host.raw: an unknown syscall number gives -ENOSYS"; else chk "$($T/zy < tests/programs/rawsys.zc)" "-1" "Host.raw: unavailable on this host"; fi
 	if [ "$(uname -m)" = x86_64 ]; then chk "$($T/zy < tests/programs/rawpid.zc)" "1" "Host.raw: getpid (39 on x86-64) answers"; fi
 }
 
 s_micro() {
 	T=$ROOT/micro
-	gcc -pthread -DZY_THREADS -O2 -w -fwrapv src/micro/micro.c src/micro/port_linux.c -Isrc/core -Isrc/micro -o $T/zym || exit 1
+	$CC -pthread -DZY_THREADS -O2 -w -fwrapv src/micro/micro.c src/micro/port_linux.c $GI -Isrc/micro -o $T/zym || exit 1
 	run $T/zym "micro"
 	python3 tests/drivers/array_methods_test.py $T/zym > $T/arrays.out 2>&1; r=$?
 	grep -v '^ok' $T/arrays.out
@@ -233,8 +248,9 @@ s_micro() {
 	python3 tests/drivers/actor_test.py $T/zym > $T/actor.out 2>&1; r=$?
 	grep -v '^ok' $T/actor.out
 	chk $r 0 "micro isolated actor acceptance, rejection and regression fixtures"
-	if command -v node >/dev/null; then
-		python3 tests/drivers/fuzz_compiler.py $ROOT/zy $T/zym --js > $T/fuzz.out 2>&1; r=$?
+	if command -v node >/dev/null && command -v tsc >/dev/null && node src/js/mklayout.js --map $MAP --out $T/jsvm >/dev/null \
+		&& cp $ROOT/s1/genome.bin $T/jsvm/ && tsc src/js/tinyvm.ts --target es2020 --lib es2020,dom --module commonjs --outDir $T/jsvm; then
+		python3 tests/drivers/fuzz_compiler.py $ROOT/zy $T/zym --js $T/jsvm/tinyvm.js > $T/fuzz.out 2>&1; r=$?
 	else
 		python3 tests/drivers/fuzz_compiler.py $ROOT/zy $T/zym > $T/fuzz.out 2>&1; r=$?
 	fi
@@ -245,8 +261,8 @@ s_micro() {
 	chk $r 0 "malformed compiler input fuzz and host agreement"
 	selfc $T/zym $T/gm.bin
 	cmp -s $T/g1.bin $T/gm.bin && chk 1 1 "microcore self-compile matches" || chk 0 1 "microcore self-compile matches"
-	gcc -ffreestanding -w -c src/micro/micro.c -Isrc/core -Isrc/micro -o $T/micro.o && gcc -ffreestanding -w -c src/micro/port_stub.c -Isrc/core -Isrc/micro -o $T/stub.o && chk 1 1 "microcore and the stub port compile freestanding" || chk 0 1 "microcore and the stub port compile freestanding"
-	gcc -pthread -O2 -w -fwrapv -DJTYPE=int -DZY_SOFTFLOAT -DZYINTERP src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core -o $T/zysoft || exit 1
+	$CC -ffreestanding -w -c src/micro/micro.c $GI -Isrc/micro -o $T/micro.o && $CC -ffreestanding -w -c src/micro/port_stub.c $GI -Isrc/micro -o $T/stub.o && chk 1 1 "microcore and the stub port compile freestanding" || chk 0 1 "microcore and the stub port compile freestanding"
+	$CC -pthread -O2 -w -fwrapv -DJTYPE=int -DZY_SOFTFLOAT -DZYINTERP src/core/core.c src/core/io_linux.c $GI -o $T/zysoft || exit 1
 		chk "$($T/zysoft < tests/programs/float.zc)" "4.000000 4.500000 3.000000 2.500000 2.500000 0.001500 0.100000 -0.125000 inf -inf nan 1 1 1 0 0 3 -3 3.000000 -2.000000 2" "soft-float fallback matches the hardware line"
 		chk "$($T/zysoft < tests/programs/ftruth.zc)" "00111000110107" "soft-float negative zero is false"
 		chk "$($T/zysoft < tests/programs/fo3.zc)" "5997 5997 4.000000 nan 0 3.250000 1 0 0" "soft-float o3 float ops match"
@@ -256,7 +272,7 @@ s_micro() {
 s_small() {
 	T=$ROOT/small
 	# smaller machines. addresses are literals, so each size is its own genome.
-	gcc -O2 -w -fwrapv src/tools/genmap.c -Isrc/core -Ibuild/core -o $T/genmap || exit 1
+	$CC -O2 -w -fwrapv src/tools/genmap.c $GI -o $T/genmap || exit 1
 	$T/genmap --preset default --check >/dev/null && chk 1 1 "default map matches the checked-in sources" || chk 0 1 "default map matches the checked-in sources"
 	$T/genmap --preset small -o $T/small || exit 1
 	$T/genmap --mode compiler --name small --heap-lo 8192 --heap 20480 --types 8192 \
@@ -265,13 +281,13 @@ s_small() {
 	cmp -s $T/small/memmap.h $T/small-flags/memmap.h && cmp -s $T/small/rt.zc $T/small-flags/rt.zc \
 		&& cmp -s $T/small/compiler.zc $T/small-flags/compiler.zc && cmp -s $T/small/map.txt $T/small-flags/map.txt \
 		&& chk 1 1 "compiler flags reproduce the small map" || chk 0 1 "compiler flags reproduce the small map"
-	cp src/tools/zc0.c src/core/fops.h src/core/bops.h src/core/stack.h $T/small/
-	gcc -O1 -w -fwrapv $T/small/zc0.c -o $T/zc0s || exit 1
-	cat $T/small/rt.zc $T/small/compiler.zc | $T/zc0s > $T/small/genome.h || exit 1
-	cp src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/micro/port_stub.c src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h $T/small/
-	gcc -pthread -DZY_THREADS -O2 -w -fwrapv $T/small/micro.c $T/small/port_linux.c -o $T/zyms || exit 1
-	gcc -pthread -O2 -w -fwrapv -DJTYPE=int $T/small/core.c $T/small/io_linux.c -o $T/zys || exit 1
-	gcc -ffreestanding -w -c $T/small/micro.c -o $T/micro_s.o && gcc -ffreestanding -w -c $T/small/port_stub.c -o $T/stub_s.o && chk 1 1 "small microcore compiles freestanding" || chk 0 1 "small microcore compiles freestanding"
+	cp src/tools/zc0.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h $T/small/
+	$CC -O1 -w -fwrapv $T/small/zc0.c -o $T/zc0s || exit 1
+	cat $T/small/rt.zc src/core/core.zc $T/small/compiler.zc | $T/zc0s > $T/small/genome.bin || exit 1
+	cp src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/micro/port_stub.c src/core/core.c src/core/io_linux.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h $T/small/
+	$CC -pthread -DZY_THREADS -O2 -w -fwrapv $T/small/micro.c $T/small/port_linux.c -o $T/zyms || exit 1
+	$CC -pthread -O2 -w -fwrapv -DJTYPE=int $T/small/core.c $T/small/io_linux.c -o $T/zys || exit 1
+	$CC -ffreestanding -w -c $T/small/micro.c -o $T/micro_s.o && $CC -ffreestanding -w -c $T/small/port_stub.c -o $T/stub_s.o && chk 1 1 "small microcore compiles freestanding" || chk 0 1 "small microcore compiles freestanding"
 	sameout() { # $1 = other vm, $2 = label, $3 = source file
 		local a b
 		a=$($T/zy < "$3" 2>&1 | tr '\n' '/')
@@ -309,15 +325,15 @@ s_runonly() {
 	# its own run map: the run-only image is built against this one, and the
 	# small-machine section lays out its own rather than sharing this
 	$T/genmap --preset run -o $T/run || exit 1
-	cp src/tools/zc0.c src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/micro/port_stub.c src/core/fops.h src/core/bops.h src/core/stack.h $T/run/
-	gcc -O1 -w -fwrapv $T/run/zc0.c -o $T/zc0r || exit 1
+	cp src/tools/zc0.c src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/micro/port_stub.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h $T/run/
+	$CC -O1 -w -fwrapv $T/run/zc0.c -o $T/zc0r || exit 1
 	runonly() { # $1 label, $2 source. the program is already in the image, so it reads no source.
 		# the map is sized to the program: src/tools/automap.sh lays it out for the image's own length
 		local a b d=$T/run-$1 input=$2
 		if [ "$1" = gc ]; then input=$T/collector-progress.zc; sed 's/f >= 990/f > 0/' "$2" > "$input"; fi
 		GENMAP=$T/genmap bash src/tools/automap.sh run $d src/runtime/run.zc "$input" >/dev/null || { chk 0 1 "run $1 builds"; return; }
-		cp src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/micro/port_stub.c src/core/fops.h src/core/bops.h src/core/stack.h $d/
-		gcc -pthread -DZY_THREADS -O2 -w -fwrapv $d/micro.c $d/port_linux.c -o $T/zymr || { chk 0 1 "run $1 links"; return; }
+		cp src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/micro/port_stub.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h $d/
+		$CC -pthread -DZY_THREADS -O2 -w -fwrapv $d/micro.c $d/port_linux.c -o $T/zymr || { chk 0 1 "run $1 links"; return; }
 		a=$($T/zy < "$input" 2>&1 | tr '\n' '/')
 		b=$($T/zymr </dev/null 2>&1 | tr '\n' '/')
 		chk "$b" "$a" "run $1"
@@ -334,12 +350,12 @@ s_runonly() {
 	runonly strings tests/programs/strings.zc
 	runonly strings-ex examples/strings.zc
 	runonly share tests/programs/share.zc
-	d=$T/run-echo; GENMAP=$T/genmap bash src/tools/automap.sh run $d src/runtime/run.zc examples/echo.zc >/dev/null && cp src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/micro/port_stub.c src/core/fops.h src/core/bops.h src/core/stack.h $d/ \
-		&& gcc -pthread -DZY_THREADS -O2 -w -fwrapv $d/micro.c $d/port_linux.c -o $T/zymr \
+	d=$T/run-echo; GENMAP=$T/genmap bash src/tools/automap.sh run $d src/runtime/run.zc examples/echo.zc >/dev/null && cp src/micro/micro.c src/micro/micro_port.h src/micro/port_linux.c src/micro/port_stub.c src/core/fops.h src/core/bops.h src/core/stack.h src/core/genome.h $d/ \
+		&& $CC -pthread -DZY_THREADS -O2 -w -fwrapv $d/micro.c $d/port_linux.c -o $T/zymr \
 		&& chk "$(printf 'abc\n' | $T/zymr | tr '\n' '/')" "$( (cat examples/echo.zc; printf '`abc\n') | $T/zy | tr '\n' '/')" "run echo" \
 		|| chk 0 1 "run echo"
 	# zcc: a program becomes a static binary that runs without stdin and with a held-open pipe
-	if CC=gcc src/tools/zcc -o $T/zcc-hello examples/hello.zc >/dev/null 2>&1; then
+	if src/tools/zcc -o $T/zcc-hello examples/hello.zc >/dev/null 2>&1; then
 		chk "$($T/zcc-hello < /dev/null)" "hello, world!" "zcc: hello, static"
 		chk "$(sleep 2 | timeout 5 $T/zcc-hello; echo $?)" "hello, world!
 0" "zcc: a program that never reads stdin does not wait for it"
@@ -348,7 +364,7 @@ s_runonly() {
 	printf 'fn main() {\n\tput_n(1\n\treturn 0;\n}\n' > $T/zcc-bad.zc
 	src/tools/zcc -o $T/zcc-bad $T/zcc-bad.zc </dev/null >/dev/null 2>&1; r=$?
 	chk "$r $( [ -e $T/zcc-bad ] && echo yes || echo no)" "1 no" "zcc: a bad program exits 1 and writes no binary"
-	gcc -ffreestanding -w -c $T/run-echo/micro.c -o $T/micro_r.o && gcc -ffreestanding -w -c $T/run-echo/port_stub.c -o $T/stub_r.o && chk 1 1 "run-only microcore compiles freestanding" || chk 0 1 "run-only microcore compiles freestanding"
+	$CC -ffreestanding -w -c $T/run-echo/micro.c -o $T/micro_r.o && $CC -ffreestanding -w -c $T/run-echo/port_stub.c -o $T/stub_r.o && chk 1 1 "run-only microcore compiles freestanding" || chk 0 1 "run-only microcore compiles freestanding"
 }
 
 s_bare() {
@@ -427,13 +443,13 @@ s_bare() {
 s_jit() {
 	T=$ROOT/jit
 	if command -v aarch64-linux-gnu-gcc >/dev/null && command -v qemu-aarch64 >/dev/null; then
-		aarch64-linux-gnu-gcc -pthread -O2 -w -fwrapv -DJTYPE=int -static src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core -o $T/zyj || exit 1
+		aarch64-linux-gnu-gcc -pthread -O2 -w -fwrapv -DJTYPE=int -static src/core/core.c src/core/io_linux.c $GI -o $T/zyj || exit 1
 		printf '#!/bin/sh\nexec qemu-aarch64 %s "$@"\n' $T/zyj > $T/jit; chmod +x $T/jit
 		run $T/jit "jit"
 		chk "$(ZYTRACE=1 $T/jit < tests/programs/o3.zc 2>&1 | grep -c 'bytes of arm64')" "8" "jit compiles every o3 region to arm64"
 		selfc $T/jit $T/gj.bin; cmp -s $T/g1.bin $T/gj.bin && chk 1 1 "jit self-compile matches" || chk 0 1 "jit self-compile matches"
 		# native calls need a dynamic binary (a static one has no dlsym), run against the aarch64 libc
-		if [ -d /usr/aarch64-linux-gnu/lib ] && aarch64-linux-gnu-gcc -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core -o $T/zyjd -ldl 2>/dev/null; then
+		if [ -d /usr/aarch64-linux-gnu/lib ] && aarch64-linux-gnu-gcc -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c $GI -o $T/zyjd -ldl 2>/dev/null; then
 			chk "$(qemu-aarch64 -L /usr/aarch64-linux-gnu $T/zyjd < tests/programs/cabi.zc | md5sum)" "$(md5sum < tests/programs/cabi.expected)" "jit native calls and callbacks (extern, cfunc)"
 			chk "$(qemu-aarch64 -L /usr/aarch64-linux-gnu $T/zyjd < tests/programs/cabi_o3.zc | md5sum)" "$(md5sum < tests/programs/cabi_o3.expected)" "jit native calls from o3 code, stack arguments"
 			chk "$(qemu-aarch64 -L /usr/aarch64-linux-gnu $T/zyjd < tests/programs/cabi_sized.zc | md5sum)" "$(md5sum < tests/programs/cabi_sized.expected)" "jit native calls with f32 and the sized integers"
@@ -449,7 +465,9 @@ s_llvm() {
 	T=$ROOT/llvm
 	# llvm-config can exist without the headers and static libs (a runtime-only install), so the gate is a real build
 	llvm_ok=0
-	if command -v llvm-config >/dev/null && gcc -pthread -O2 -w -fwrapv -DJTYPE=int -DZYLLVM $(llvm-config --cflags) src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core -o $T/zyl $(llvm-config --ldflags --libs) 2>/dev/null; then llvm_ok=1; fi
+	# LLVM_CONFIG picks the llvm build when the one on PATH has no headers (e.g. /usr/lib/llvm-20/bin/llvm-config)
+	local lc=${LLVM_CONFIG:-llvm-config}
+	if command -v $lc >/dev/null && $CC -pthread -O2 -w -fwrapv -DJTYPE=int -DZYLLVM $($lc --cflags) src/core/core.c src/core/io_linux.c $GI -o $T/zyl $($lc --ldflags --libs) 2>/dev/null; then llvm_ok=1; fi
 	if [ $llvm_ok = 1 ]; then
 		run $T/zyl "llvm"
 		chk "$(ZYTRACE=1 $T/zyl < tests/programs/o3.zc 2>&1 | grep -c 'compiled by llvm')" "8" "llvm compiles every o3 region"
@@ -558,11 +576,8 @@ s_lsp() {
 			node tests/drivers/diagcache_test.js > $T/dcache.out 2>&1; r=$?
 			grep -v '^ok' $T/dcache.out
 			chk $r 0 "lsp: the diagnostics cache keys and store ($(grep -c '^ok' $T/dcache.out) checks)"
-			node tests/drivers/ext_cache_test.js > $T/ecache.out 2>&1; r=$?
-			grep -v '^ok' $T/ecache.out
-			chk $r 0 "lsp: the extension's cache, end to end ($(grep -c '^ok' $T/ecache.out) checks)"
 			# the same server as WebAssembly, through the extension's host (needs clang)
-			if command -v clang >/dev/null && clang --print-targets 2>/dev/null | grep -q wasm32 && LSP_BUILD_DIR=$T/lsp LSP_REUSE_BUILD=1 bash src/tools/mklspwasm.sh $T/lsp/lsp.wasm >/dev/null 2>&1; then
+			if sh src/tools/findcc.sh --wasm >/dev/null 2>&1 && LSP_BUILD_DIR=$T/lsp LSP_REUSE_BUILD=1 bash src/tools/mklspwasm.sh $T/lsp/lsp.wasm >/dev/null 2>&1; then
 				node tests/drivers/hover_surface_test.js --wasm $T/lsp/lsp.wasm > $T/hoversurfacewasm.out 2>&1; r=$?
 				grep -v '^ok' $T/hoversurfacewasm.out
 				chk $r 0 "lsp: embedded and asm hovers through the wasm host"
@@ -575,7 +590,8 @@ s_lsp() {
 			else echo "skip lsp wasm tests (no clang with wasm32)"; fi
 			# the same server run by the javascript vm, the extension's fallback when wasm is not there.
 			# the vm starts at the image's heap and grows on the heap's request, so a long document is the test
-			node src/js/extract_lsp.js >/dev/null && mkdir -p $T/vmserver && cp build/js/tinyvm.js build/js/layout.js build/js/lsp.json $T/vmserver/
+			node src/js/extract_lsp.js --lsp $T/lsp --out $T/vmserver >/dev/null && node src/js/mklayout.js --map $MAP --out $T/vmserver >/dev/null \
+				&& tsc src/js/tinyvm.ts --target es2020 --lib es2020,dom --module commonjs --outDir $T/vmserver
 			node tests/drivers/hover_surface_test.js --vm $T/vmserver > $T/hoversurfacevm.out 2>&1; r=$?
 			grep -v '^ok' $T/hoversurfacevm.out
 			chk $r 0 "lsp: embedded and asm hovers through the javascript host"
@@ -590,6 +606,12 @@ s_lsp() {
 				grep -v '^ok' $T/streamhost.out
 				chk $r 0 "lsp: the wasm and vm servers stream and drop stale checks"
 			fi
+			# the extension's client end to end, with the server files the package would carry
+			mkdir -p $T/extserver && cp $T/vmserver/tinyvm.js $T/vmserver/layout.js $T/vmserver/lsp.json $T/vmserver/lsp.bin $T/extserver/
+			[ -f $T/lsp/lsp.wasm ] && cp $T/lsp/lsp.wasm $T/extserver/
+			node tests/drivers/ext_cache_test.js $T/extserver > $T/ecache.out 2>&1; r=$?
+			grep -v '^ok' $T/ecache.out
+			chk $r 0 "lsp: the extension's cache, end to end ($(grep -c '^ok' $T/ecache.out) checks)"
 		else echo "skip lsp protocol tests (no node)"; fi
 	else chk 0 1 "lsp server builds"; fi
 }
@@ -597,36 +619,39 @@ s_lsp() {
 s_js() {
 	T=$ROOT/js
 	# the javascript vm, and the microcore as webassembly. both run the same genome
-	if command -v node >/dev/null; then
-		chk "$(node -e "console.log(require('./build/js/genome.json').glen)")" "$(grep -m1 '#define GLEN' build/core/genome.h | awk '{print $3}')" "build/js/genome.json is up to date"
-		chk "$(node build/js/tinyvm.js examples/hello.zc)" "hello, world!" "js vm: hello"
-		chk "$(node build/js/tinyvm.js examples/fact.zc | tail -1)" "3628800" "js vm: factorial"
-		chk "$(node build/js/tinyvm.js examples/primes.zc | tail -1)" "widest gap: 72, after 31397" "js vm: primes"
-		chk "$(node build/js/tinyvm.js tests/programs/growone.zc)" "12 1" "js vm: a block past the initial heap grows the machine"
-		chk "$(node build/js/tinyvm.js tests/programs/replace_owner.zc)" "$(cat tests/programs/replace_owner.expected)" "js vm: replacement ownership and cleanup"
-		if command -v clang >/dev/null && command -v wasm-ld >/dev/null && clang --print-targets 2>/dev/null | grep -q wasm32; then
-			bash src/web/build.sh $T/zc.wasm >/dev/null && node tests/drivers/wasm_test.js $T/zc.wasm > $T/wasm.out 2>&1; r=$?
+	if command -v node >/dev/null && command -v tsc >/dev/null; then
+		# the vm as make js builds it, with the fixpoint genome beside it
+		node src/js/mklayout.js --map $MAP --out $T/jsvm >/dev/null && cp $ROOT/s1/genome.bin $T/jsvm/genome.bin \
+			&& tsc src/js/tinyvm.ts --target es2020 --lib es2020,dom --module commonjs --outDir $T/jsvm || chk 0 1 "js vm builds"
+		chk "$(node $T/jsvm/tinyvm.js examples/hello.zc)" "hello, world!" "js vm: hello"
+		chk "$(node $T/jsvm/tinyvm.js examples/fact.zc | tail -1)" "3628800" "js vm: factorial"
+		chk "$(node $T/jsvm/tinyvm.js examples/primes.zc | tail -1)" "widest gap: 72, after 31397" "js vm: primes"
+		chk "$(node $T/jsvm/tinyvm.js tests/programs/growone.zc)" "12 1" "js vm: a block past the initial heap grows the machine"
+		chk "$(node $T/jsvm/tinyvm.js tests/programs/replace_owner.zc)" "$(cat tests/programs/replace_owner.expected)" "js vm: replacement ownership and cleanup"
+		if sh src/tools/findcc.sh --wasm >/dev/null 2>&1 && command -v wasm-ld >/dev/null; then
+			GENOME_DIR=$ROOT/s1 MAP_DIR=$MAP bash src/web/build.sh $T/zc.wasm >/dev/null && node tests/drivers/wasm_test.js $T/zc.wasm > $T/wasm.out 2>&1; r=$?
 			grep -v '^ok' $T/wasm.out
 			chk $r 0 "wasm: the microcore in webassembly ($(grep -c '^ok' $T/wasm.out) checks)"
 			node tests/drivers/fuzz_wasm.js $T/zc.wasm > $T/fuzzw.out 2>&1; r=$?
 			grep -v '^ok' $T/fuzzw.out
 			chk $r 0 "wasm: compiler/runtime/stdlib differential fuzz"
-		else echo "skip wasm (no clang with the wasm32 target, or no wasm-ld)"; fi
-	else echo "skip js and wasm (no node)"; fi
+		else echo "skip wasm (no clang with the wasm32 target and #embed, or no wasm-ld)"; fi
+	else echo "skip js and wasm (no node or tsc)"; fi
 }
 
 s_make() {
 	T=$ROOT/make
 	# the makefile builds the programs and the run-only image tool
 	if command -v make >/dev/null; then
-		make -s BIN=$T/mbin B=$T/mbuild all >/dev/null 2>&1 && chk "$($T/mbin/zy < examples/hello.zc)" "hello, world!" "make: bin/zy runs a program" || chk 0 1 "make: all builds"
-		python3 tests/drivers/cli_help_test.py --group binaries --bin-dir $T/mbin > $T/help.out 2>&1; r=$?
+		# from an empty build directory, as a fresh checkout would be
+		make -s B=$T/mbuild all >/dev/null 2>&1 && chk "$($T/mbuild/bin/zy < examples/hello.zc)" "hello, world!" "make: build/bin/zy runs a program" || chk 0 1 "make: all builds"
+		python3 tests/drivers/cli_help_test.py --group binaries --bin-dir $T/mbuild/bin > $T/help.out 2>&1; r=$?
 		grep -v '^ok' $T/help.out
 		chk $r 0 "command-line help, invalid options and existing lsp source modes"
 		python3 tests/drivers/cli_help_test.py --group scripts > $T/scripthelp.out 2>&1; r=$?
 		grep -v '^ok' $T/scripthelp.out
 		chk $r 0 "build-script help exits without reading input or starting a build"
-		make -s BIN=$T/mbin B=$T/mbuild run PROG=examples/hello.zc >/dev/null 2>&1 && chk "$($T/mbuild/run/zymr </dev/null)" "hello, world!" "make: run PROG= builds a run-only image" || chk 0 1 "make: run builds"
+		make -s B=$T/mbuild run PROG=examples/hello.zc >/dev/null 2>&1 && chk "$($T/mbuild/run/zymr </dev/null)" "hello, world!" "make: run PROG= builds a run-only image" || chk 0 1 "make: run builds"
 	else echo "skip make (not installed)"; fi
 }
 
@@ -634,7 +659,7 @@ s_make() {
 # every block in it is one of those examples (tests/drivers/learn.py)
 s_learn() {
 	T=$ROOT/learn
-	gcc -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c -Isrc/core -Ibuild/core -o $T/zy
+	$CC -pthread -O2 -w -fwrapv -DJTYPE=int src/core/core.c src/core/io_linux.c $GI -o $T/zy
 	# learn.py prints its own ok and FAIL lines, which the tally below counts
 	python3 tests/drivers/learn.py $T/zy; true
 }
diff --git a/tests/test_win.ps1 b/tests/test_win.ps1
index 0edc86c..953e875 100644
--- a/tests/test_win.ps1
+++ b/tests/test_win.ps1
@@ -1,17 +1,29 @@
 # TinyVM Windows test suite (PowerShell implementation of test.sh)
 $ErrorActionPreference = "Stop"
 
-# detect compiler (prioritizing LLVM-MinGW with UCRT headers)
+# the suite reads nothing from build\: it lays out the default map, bootstraps the
+# compiler and builds every executable in its own temporary directory. the cores
+# take their genome in with c23 #embed, so the compiler must be clang 19 or gcc 15.
+$tempDir = [System.IO.Path]::Combine([System.IO.Path]::GetTempPath(), "tinyvm_test_" + [System.Guid]::NewGuid().ToString("N"))
+New-Item -ItemType Directory -Path "$tempDir\s0", "$tempDir\s1", "$tempDir\probe" -Force | Out-Null
+[IO.File]::WriteAllText("$tempDir\probe\probe.bin", "ab")
+[IO.File]::WriteAllText("$tempDir\probe\probe.c", "static const unsigned char probe[] = {`n#embed `"probe.bin`"`n};`nint main(void) { return sizeof probe == 2 ? 0 : 1; }`n")
+function Test-Embed($compiler) {
+    & $compiler -w "--embed-dir=$tempDir\probe" "$tempDir\probe\probe.c" -o "$tempDir\probe\probe.exe" 2>$null | Out-Null
+    return $LASTEXITCODE -eq 0
+}
+# detect a compiler with #embed (CC first, then LLVM-MinGW with UCRT headers, then PATH)
+$cc = $null
+$candidates = @()
+if ($env:CC) { $candidates += $env:CC }
 $llvmMinGW = Get-ChildItem "$env:LOCALAPPDATA\Microsoft\WinGet\Packages\MartinStorsjo.LLVM-MinGW*\llvm-mingw*\bin" -ErrorAction SilentlyContinue
-if ($llvmMinGW) {
-    $env:Path = "$($llvmMinGW[0].FullName);$env:Path"
-    $cc = "clang"
-} elseif (Get-Command clang -ErrorAction SilentlyContinue) {
-    $cc = "clang"
-} elseif (Get-Command gcc -ErrorAction SilentlyContinue) {
-    $cc = "gcc"
-} else {
-    Write-Error "No C compiler (clang or gcc) found in PATH."
+if ($llvmMinGW) { $candidates += "$($llvmMinGW[0].FullName)\clang.exe" }
+$candidates += @("clang", "gcc", "$env:ProgramFiles\LLVM\bin\clang.exe")
+foreach ($c in $candidates) {
+    if ((Get-Command $c -ErrorAction SilentlyContinue) -and (Test-Embed $c)) { $cc = $c; break }
+}
+if (-not $cc) {
+    Write-Error "No C compiler with #embed support (clang 19 or gcc 15 and later) was found."
     exit 1
 }
 
@@ -21,9 +33,6 @@ Write-Host "====================================================================
 Write-Host "Compiler: $cc"
 Write-Host ""
 
-$tempDir = [System.IO.Path]::Combine([System.IO.Path]::GetTempPath(), "tinyvm_test_" + [System.Guid]::NewGuid().ToString("N"))
-New-Item -ItemType Directory -Path "$tempDir\s0", "$tempDir\s1" -Force | Out-Null
-
 $totalPassed = 0
 $totalFailed = 0
 
@@ -40,41 +49,41 @@ function Report-Result($success, $name, $detail = "") {
 try {
     # --- 1. bootstrap & fixpoint ---
     Write-Host "=== 1. Bootstrap and Fixpoint Verification ===" -ForegroundColor Yellow
-    & $cc -fwrapv -O1 -w src\tools\zc0.c -Isrc/core -o "$tempDir\zc0.exe"
-    & $cc -fwrapv -O1 -w src\tools\mkgenome.c -Isrc/core -o "$tempDir\mkgenome.exe"
+    # the default map, as make writes it, and the tools built against it
+    & $cc -fwrapv -O2 -w src\tools\genmap.c -o "$tempDir\genmap.exe"
+    cmd.exe /c "`"$tempDir\genmap.exe`" --preset default --check -o `"$tempDir\map`" >nul 2>nul"
+    Report-Result ($LASTEXITCODE -eq 0) "genmap default preset matches the sources"
+    $map = "$tempDir\map"
+    & $cc -fwrapv -O1 -w src\tools\zc0.c -Isrc/core "-I$map" -o "$tempDir\zc0.exe"
+    & $cc -fwrapv -O1 -w src\tools\mkgenome.c "-I$map" -o "$tempDir\mkgenome.exe"
 
-    Copy-Item src\core\core.c, src\core\io_win.c, src\core\memmap.h, src\core\fops.h, src\core\bops.h, src\core\stack.h -Destination "$tempDir\s0"
-    Copy-Item src\core\core.c, src\core\io_win.c, src\core\memmap.h, src\core\fops.h, src\core\bops.h, src\core\stack.h -Destination "$tempDir\s1"
-
-    cmd.exe /c "(type src\runtime\rt.zc & type src\compiler\compiler.zc) | $tempDir\zc0.exe > $tempDir\s0\genome.h"
-    & $cc -fwrapv -O2 -w -DJTYPE=int "$tempDir\s0\core.c" "$tempDir\s0\io_win.c" -o "$tempDir\zy0.exe"
+    cmd.exe /c "(type src\runtime\rt.zc & type src\core\core.zc & type src\compiler\compiler.zc) | `"$tempDir\zc0.exe`" > `"$tempDir\s0\g0.bin`""
+    cmd.exe /c "`"$tempDir\mkgenome.exe`" < `"$tempDir\s0\g0.bin`" > `"$tempDir\s0\genome.bin`""
+    & $cc -fwrapv -O2 -w -DJTYPE=int src\core\core.c src\core\io_win.c -Isrc/core "-I$map" "--embed-dir=$tempDir\s0" -o "$tempDir\zy0.exe"
 
     $bzc = [IO.File]::ReadAllText("src\tools\build.zc")
     $rt = [IO.File]::ReadAllText("src\runtime\rt.zc")
+    $core = [IO.File]::ReadAllText("src\core\core.zc")
     $cp = [IO.File]::ReadAllText("src\compiler\compiler.zc")
-    $combined = $bzc + [char]96 + $rt + $cp
+    $combined = $bzc + [char]96 + $rt + $core + $cp
     [IO.File]::WriteAllBytes("$tempDir\in.tmp", [Text.Encoding]::ASCII.GetBytes($combined))
 
     $p1 = Start-Process -FilePath "$tempDir\zy0.exe" -NoNewWindow -PassThru -RedirectStandardInput "$tempDir\in.tmp" -RedirectStandardOutput "$tempDir\g1.bin" -Wait
-    cmd.exe /c "$tempDir\mkgenome.exe < $tempDir\g1.bin > $tempDir\s1\genome.h"
+    cmd.exe /c "`"$tempDir\mkgenome.exe`" < `"$tempDir\g1.bin`" > `"$tempDir\s1\genome.bin`""
+    Report-Result ($LASTEXITCODE -eq 0) "the compiler compiles its own source"
 
-    & $cc -fwrapv -O2 -w -DJTYPE=int "$tempDir\s1\core.c" "$tempDir\s1\io_win.c" -o "$tempDir\zy1.exe"
+    & $cc -fwrapv -O2 -w -DJTYPE=int src\core\core.c src\core\io_win.c -Isrc/core "-I$map" "--embed-dir=$tempDir\s1" -o "$tempDir\zy1.exe"
     $p2 = Start-Process -FilePath "$tempDir\zy1.exe" -NoNewWindow -PassThru -RedirectStandardInput "$tempDir\in.tmp" -RedirectStandardOutput "$tempDir\g2.bin" -Wait
 
     $g1 = [IO.File]::ReadAllBytes("$tempDir\g1.bin")
     $g2 = [IO.File]::ReadAllBytes("$tempDir\g2.bin")
     $isFixpoint = [System.Linq.Enumerable]::SequenceEqual($g1, $g2)
     Report-Result $isFixpoint "Fixpoint: compiler compiles itself to identical $($g1.Length / 8) words"
-    
-    $ghRepo = (Get-FileHash "build\core\genome.h").Hash
-    $ghGen = (Get-FileHash "$tempDir\s1\genome.h").Hash
-    Report-Result ($ghRepo -eq $ghGen) "genome.h is up to date"
 
-    # --- 2. compile test executables ---
+    # --- 2. compile test executables, each carrying the fixpoint genome ---
     Write-Host "`n=== 2. Compiling Test Executables ===" -ForegroundColor Yellow
-    & $cc -fwrapv -O2 -w -DJTYPE=int src\core\core.c src\core\io_win.c -Isrc/core -o "$tempDir\zy.exe"
-    & $cc -fwrapv -O2 -w src\micro\micro.c src\micro\port_win.c -Isrc/core -Isrc/micro -o "$tempDir\zym.exe"
-    & $cc -fwrapv -O2 -w src\tools\genmap.c -Isrc/core -o "$tempDir\genmap.exe"
+    & $cc -fwrapv -O2 -w -DJTYPE=int src\core\core.c src\core\io_win.c -Isrc/core "-I$map" "--embed-dir=$tempDir\s1" -o "$tempDir\zy.exe"
+    & $cc -fwrapv -O2 -w src\micro\micro.c src\micro\port_win.c -Isrc/core "-I$map" "--embed-dir=$tempDir\s1" -Isrc/micro -o "$tempDir\zym.exe"
 
     # --- 3. feature tests on zy.exe ---
     Write-Host "`n=== 3. Running Feature Tests on VM Core (zy.exe) ===" -ForegroundColor Yellow
@@ -158,7 +167,7 @@ try {
         $pass = 0
         $fail = 0
         foreach ($f in $files) {
-            $want = ((Get-Content $f.FullName -TotalCount 1) -replace '^// expect:\s*').Trim()
+            $want = ((Get-Content $f.FullName | Where-Object { $_ -match '^// expect:' } | Select-Object -First 1) -replace '^// expect:\s*').Trim()
             $got = (Get-Content $f.FullName -Raw | & "$tempDir\zy.exe" 2>&1 | Select-Object -First 1)
             if ($got -and $got.Contains($want)) {
                 $pass++
@@ -172,9 +181,6 @@ try {
 
     # --- 6. tool verification ---
     Write-Host "`n=== 6. Memory Map Tool Verification (genmap.exe) ===" -ForegroundColor Yellow
-    cmd.exe /c "`"$tempDir\genmap.exe`" --preset default --check >nul 2>nul"
-    Report-Result ($LASTEXITCODE -eq 0) "genmap default preset check passed"
-
     cmd.exe /c "`"$tempDir\genmap.exe`" --preset small -o `"$tempDir\small`" >nul 2>nul"
     Report-Result ($LASTEXITCODE -eq 0) "genmap small preset generated"
 
@@ -182,21 +188,28 @@ try {
     Write-Host "`n=== 7. ZC Language Server (zclsp.exe) ===" -ForegroundColor Yellow
     # the server is the real compiler in check mode plus src\lsp\server.zc, on its own map
     $lspDir = "$tempDir\lsp"
-    New-Item -ItemType Directory -Force "$lspDir\src" | Out-Null
-    # two passes: compile once to learn the genome length, then lay the map out again for that length
-    $lspSrc = "(type `"$lspDir\map\rt.zc`" & type `"$lspDir\map\compiler.zc`" & type src\lsp\server.zc)"
-    cmd.exe /c "`"$tempDir\genmap.exe`" --preset lsp --grow -o `"$lspDir\map`" >nul 2>nul"
-    & $cc -fwrapv -O1 -w src\tools\zc0.c "-I$lspDir\map" -Isrc/core -o "$lspDir\zc0.exe"
-    cmd.exe /c "$lspSrc | `"$lspDir\zc0.exe`" > `"$lspDir\genome.h`""
-    $glen = [int]((Select-String -Path "$lspDir\genome.h" -Pattern '#define\s+GLEN\s+(\d+)' | Select-Object -First 1).Matches[0].Groups[1].Value)
+    New-Item -ItemType Directory -Force "$lspDir" | Out-Null
+    # the steps of src/tools/automap.sh lsp with DOCS=1: compile once to learn the genome
+    # length, lay the map out for it, then again with the documentation the hovers read
+    function Build-LspImage($slot, $define, $out) {
+        if (Test-Path "$lspDir\map") { Remove-Item -Recurse -Force "$lspDir\map" }
+        $genomeOption = if ($slot) { "--genome $slot" } else { "" }
+        cmd.exe /c "`"$tempDir\genmap.exe`" --preset lsp --grow $genomeOption -o `"$lspDir\map`" >nul 2>nul"
+        & $cc -fwrapv -O1 -w $define src\tools\zc0.c "-I$lspDir\map" -Isrc/core -o "$lspDir\zc0.exe"
+        & $cc -fwrapv -O1 -w src\tools\mkgenome.c "-I$lspDir\map" -o "$lspDir\mkgenome.exe"
+        cmd.exe /c "(type `"$lspDir\map\rt.zc`" & type src\core\core.zc & type `"$lspDir\map\compiler.zc`" & type src\lsp\server.zc) | `"$lspDir\zc0.exe`" > `"$lspDir\raw.bin`""
+        cmd.exe /c "`"$lspDir\mkgenome.exe`" < `"$lspDir\raw.bin`" > `"$lspDir\$out`""
+        return [int]((Get-Item "$lspDir\$out").Length / 8)
+    }
+    # ZC0PLAIN defines nothing zc0 reads; it stands in for "no documentation" as one argument
+    $glen = Build-LspImage $null "-DZC0PLAIN" "image.bin"
+    $slot = [int]([math]::Ceiling($glen / 4096.0) * 4096)
+    $glen = Build-LspImage ($slot + 65536) "-DZC0DOCS" "image.bin"
     $slot = [int]([math]::Ceiling($glen / 4096.0) * 4096)
-    Remove-Item -Recurse -Force "$lspDir\map"
-    cmd.exe /c "`"$tempDir\genmap.exe`" --preset lsp --grow --genome $slot -o `"$lspDir\map`" >nul 2>nul"
-    & $cc -fwrapv -O1 -w src\tools\zc0.c "-I$lspDir\map" -Isrc/core -o "$lspDir\zc0.exe"
-    cmd.exe /c "$lspSrc | `"$lspDir\zc0.exe`" > `"$lspDir\src\lsp_genome.h`""
-    foreach ($f in 'core.c','io_win.c','fops.h','bops.h','stack.h') { Copy-Item "src\core\$f" "$lspDir\src\" }
-    Copy-Item "$lspDir\map\memmap.h" "$lspDir\src\"
-    & $cc -fwrapv -O2 -w -DJTYPE=int -DUSE_LSP_GENOME "-I$lspDir\src" "$lspDir\src\core.c" "$lspDir\src\io_win.c" -o "$lspDir\zclsp.exe"
+    $final = Build-LspImage $slot "-DZC0DOCS" "lsp_genome.bin"
+    Report-Result ($final -eq $glen) "the LSP genome keeps its length on its sized map"
+    Copy-Item "$lspDir\map\memmap.h" "$lspDir\"
+    & $cc -fwrapv -O2 -w -DJTYPE=int -DZY_SANDBOX -DUSE_LSP_GENOME src\core\core.c src\core\io_win.c -Isrc/core "-I$lspDir" "--embed-dir=$lspDir" -o "$lspDir\zclsp.exe"
     Report-Result (Test-Path "$lspDir\zclsp.exe") "zclsp.exe compiled"
 
     # CLI check: a clean file
@@ -209,7 +222,7 @@ try {
 
     # CLI check: the compiler's optimization hints
     $lspOpt = (cmd.exe /c "`"$lspDir\zclsp.exe`" < examples\opt_test.zc 2>&1") -join "`n"
-    $hints = @("is never read", "is never reassigned; make it a const", "is a shift; write << 3", "the number 1234 has no name", "new inside a loop", "stack buffer", "handed off once")
+    $hints = @("is never read", "is never reassigned; make it a const", "is a shift; write << 3", "unannotated numeric literal 1234", "new inside a loop", "stack buffer")
     foreach ($h in $hints) { Report-Result ($lspOpt.Contains($h)) "zclsp hint: $h" }
 
     # methods with this, and closures, check clean
@@ -226,23 +239,28 @@ try {
         Write-Host "  [SKIP] Node.js not detected in PATH, skipping lsp protocol tests." -ForegroundColor DarkYellow
     }
 
-    # --- 8. JavaScript / TypeScript vm runtime (build/js/tinyvm.js) ---
-    Write-Host "`n=== 8. JavaScript VM Runtime (node build/js/tinyvm.js) ===" -ForegroundColor Yellow
+    # --- 8. JavaScript / TypeScript vm runtime, built as make js builds it ---
+    Write-Host "`n=== 8. JavaScript VM Runtime (node tinyvm.js) ===" -ForegroundColor Yellow
     $nodeCmd = Get-Command node -ErrorAction SilentlyContinue
-    if ($nodeCmd) {
-        $jsHello = (node build\js\tinyvm.js examples\hello.zc 2>&1) -join "`n"
+    $tscCmd = Get-Command tsc -ErrorAction SilentlyContinue
+    if ($nodeCmd -and $tscCmd) {
+        $jsDir = "$tempDir\js"
+        node src\js\mklayout.js --map "$map\memmap.h" --out $jsDir | Out-Null
+        Copy-Item "$tempDir\s1\genome.bin" "$jsDir\genome.bin"
+        tsc src\js\tinyvm.ts --target es2020 --lib es2020,dom --module commonjs --outDir $jsDir
+        $jsHello = (node $jsDir\tinyvm.js examples\hello.zc 2>&1) -join "`n"
         Report-Result ($jsHello.Trim() -eq "hello, world!") "JS VM: hello.zc"
 
-        $jsFact = (node build\js\tinyvm.js examples\fact.zc 2>&1) -join "`n"
+        $jsFact = (node $jsDir\tinyvm.js examples\fact.zc 2>&1) -join "`n"
         Report-Result ($jsFact.Contains("3628800")) "JS VM: fact.zc"
 
-        $jsPrimes = (node build\js\tinyvm.js examples\primes.zc 2>&1) -join "`n"
+        $jsPrimes = (node $jsDir\tinyvm.js examples\primes.zc 2>&1) -join "`n"
         Report-Result ($jsPrimes.Contains("widest gap: 72")) "JS VM: primes.zc"
 
-        $jsMandel = (node build\js\tinyvm.js examples\mandel.zc 2>&1) -join "`n"
+        $jsMandel = (node $jsDir\tinyvm.js examples\mandel.zc 2>&1) -join "`n"
         Report-Result ($jsMandel.Contains("*") -or $jsMandel.Contains(".")) "JS VM: mandel.zc (custom fmul enhancement)"
     } else {
-        Write-Host "  [SKIP] Node.js not detected in PATH, skipping JS tests." -ForegroundColor DarkYellow
+        Write-Host "  [SKIP] Node.js or tsc not detected in PATH, skipping JS tests." -ForegroundColor DarkYellow
     }
 }
 finally {
diff --git a/tinyvm.bat b/tinyvm.bat
index 9a457eb..7d0676d 100755
--- a/tinyvm.bat
+++ b/tinyvm.bat
@@ -7,65 +7,83 @@ if /i "%~1"=="help" goto :show_help
 if /i "%~1"=="--help" goto :show_help
 if /i "%~1"=="-h" goto :show_help
 
+REM everything built or generated goes under build\ (executables in build\bin);
+REM the tree holds sources only. the cores take their genome in with c23 #embed,
+REM so the compiler has to be clang 19 or gcc 15 or later.
+
 REM =========================================================================
 REM Compiler Detection & Environment Setup
 REM =========================================================================
 
 set "CC_NAME="
-
-REM preserve a compiler selected by the caller.
+if not exist "build\probe" mkdir "build\probe"
+> "build\probe\probe.bin" echo ab
+> "build\probe\probe.c" echo static const unsigned char probe[] = {
+>> "build\probe\probe.c" echo #embed "probe.bin"
+>> "build\probe\probe.c" echo };
+>> "build\probe\probe.c" echo int main(void) { return sizeof probe ^> 0 ? 0 : 1; }
+
+REM preserve a compiler selected by the caller, if it can #embed.
 if defined CC (
-    set "CC_NAME=Configured [%CC%]"
-    goto :has_compiler
+    call :probe_cc "%CC%"
+    if not errorlevel 1 (
+        set "CC_NAME=Configured [%CC%]"
+        goto :has_compiler
+    )
+    echo [ERROR] CC=%CC% does not support #embed; clang 19 or gcc 15 is needed.
+    exit /b 1
 )
 
-REM 1. Search WinGet LLVM-MinGW portable packages first (self-contained with CRT headers)
+REM 1. WinGet LLVM-MinGW portable packages (self-contained with CRT headers)
 for /d %%D in ("%LOCALAPPDATA%\Microsoft\WinGet\Packages\MartinStorsjo.LLVM-MinGW*") do (
     for /d %%B in ("%%D\llvm-mingw*") do (
         if exist "%%B\bin\clang.exe" (
-            set "PATH=%%B\bin;!PATH!"
-            set "CC=clang"
-            set "CC_NAME=LLVM-MinGW Clang [WinGet]"
-            goto :compiler_found
+            call :probe_cc "%%B\bin\clang.exe"
+            if not errorlevel 1 (
+                set "PATH=%%B\bin;!PATH!"
+                set "CC=clang"
+                set "CC_NAME=LLVM-MinGW Clang [WinGet]"
+                goto :has_compiler
+            )
         )
     )
 )
 
-REM 2. Check if clang or gcc is already in PATH
-where clang >nul 2>nul
-if %errorlevel% equ 0 (
-    set "CC=clang"
-    set "CC_NAME=Clang [in PATH]"
-    goto :compiler_found
-)
-
-where gcc >nul 2>nul
-if %errorlevel% equ 0 (
-    set "CC=gcc"
-    set "CC_NAME=GCC [in PATH]"
-    goto :compiler_found
+REM 2. clang or gcc already in PATH
+for %%C in (clang gcc) do (
+    where %%C >nul 2>nul
+    if !errorlevel! equ 0 (
+        call :probe_cc %%C
+        if not errorlevel 1 (
+            set "CC=%%C"
+            set "CC_NAME=%%C [in PATH]"
+            goto :has_compiler
+        )
+    )
 )
 
-REM 3. Search C:\Program Files\LLVM\bin
+REM 3. C:\Program Files\LLVM\bin and the x86 variant
 if exist "%ProgramFiles%\LLVM\bin\clang.exe" (
-    set "PATH=%ProgramFiles%\LLVM\bin;%PATH%"
-    set "CC=clang"
-    set "CC_NAME=LLVM Clang [Program Files]"
-    goto :compiler_found
+    call :probe_cc "%ProgramFiles%\LLVM\bin\clang.exe"
+    if not errorlevel 1 (
+        set "PATH=%ProgramFiles%\LLVM\bin;%PATH%"
+        set "CC=clang"
+        set "CC_NAME=LLVM Clang [Program Files]"
+        goto :has_compiler
+    )
 )
-
 set "PFX86=%ProgramFiles(x86)%"
 if defined PFX86 if exist "!PFX86!\LLVM\bin\clang.exe" (
-    set "PATH=!PFX86!\LLVM\bin;%PATH%"
-    set "CC=clang"
-    set "CC_NAME=LLVM Clang [Program Files x86]"
-    goto :compiler_found
+    call :probe_cc "!PFX86!\LLVM\bin\clang.exe"
+    if not errorlevel 1 (
+        set "PATH=!PFX86!\LLVM\bin;%PATH%"
+        set "CC=clang"
+        set "CC_NAME=LLVM Clang [Program Files x86]"
+        goto :has_compiler
+    )
 )
 
-:compiler_found
-if not "%CC%"=="" goto :has_compiler
-
-echo [ERROR] No suitable C compiler [clang or gcc] found on this system.
+echo [ERROR] No C compiler with #embed support [clang 19 or gcc 15 and later] was found.
 echo.
 echo Please install LLVM / Clang:
 echo   winget install MartinStorsjo.LLVM-MinGW.UCRT
@@ -74,7 +92,14 @@ echo.
 pause
 exit /b 1
 
+REM :probe_cc compiler - errorlevel 0 when it compiles a file that uses #embed
+:probe_cc
+%1 -w --embed-dir=build\probe build\probe\probe.c -o build\probe\probe.exe >nul 2>nul
+exit /b %errorlevel%
+
 :has_compiler
+REM the include and embed paths of a core that carries the compiler genome
+set "COREINC=-Isrc/core -Ibuild/core/map --embed-dir=build/core"
 
 REM Handle CLI Arguments if provided
 if not "%~1"=="" goto :handle_cli
@@ -92,29 +117,29 @@ echo   Compiler : %CC_NAME%
 echo   Working  : %CD%
 echo -------------------------------------------------------------------------------
 echo   executable status:
-if exist "bin\zy.exe"       ( echo     [X] bin\zy.exe       - VM core interpreter ) else ( echo     [ ] bin\zy.exe       - not built )
-if exist "bin\zym.exe"      ( echo     [X] bin\zym.exe      - portable microcore ) else ( echo     [ ] bin\zym.exe      - not built )
-if exist "bin\zc0.exe"      ( echo     [X] bin\zc0.exe      - stage 0 bootstrap compiler ) else ( echo     [ ] bin\zc0.exe      - not built )
-if exist "bin\mkgenome.exe" ( echo     [X] bin\mkgenome.exe - genome header generator ) else ( echo     [ ] bin\mkgenome.exe - not built )
-if exist "bin\genmap.exe"   ( echo     [X] bin\genmap.exe   - memory map generator ) else ( echo     [ ] bin\genmap.exe   - not built )
-if exist "bin\zclsp.exe"    ( echo     [X] bin\zclsp.exe    - language server protocol ^& highlighter ) else ( echo     [ ] bin\zclsp.exe    - not built )
+if exist "build\bin\zy.exe"       ( echo     [X] build\bin\zy.exe       - VM core interpreter ) else ( echo     [ ] build\bin\zy.exe       - not built )
+if exist "build\bin\zym.exe"      ( echo     [X] build\bin\zym.exe      - portable microcore ) else ( echo     [ ] build\bin\zym.exe      - not built )
+if exist "build\bin\zc0.exe"      ( echo     [X] build\bin\zc0.exe      - stage 0 bootstrap compiler ) else ( echo     [ ] build\bin\zc0.exe      - not built )
+if exist "build\bin\mkgenome.exe" ( echo     [X] build\bin\mkgenome.exe - genome image checker ) else ( echo     [ ] build\bin\mkgenome.exe - not built )
+if exist "build\bin\genmap.exe"   ( echo     [X] build\bin\genmap.exe   - memory map generator ) else ( echo     [ ] build\bin\genmap.exe   - not built )
+if exist "build\bin\zclsp.exe"    ( echo     [X] build\bin\zclsp.exe    - language server protocol ^& highlighter ) else ( echo     [ ] build\bin\zclsp.exe    - not built )
 echo ===============================================================================
-echo   [1] build VM core (bin\zy.exe)
-echo   [2] build microcore (bin\zym.exe)
-echo   [3] build bootstrap tools (bin\zc0.exe, bin\mkgenome.exe, bin\genmap.exe)
-echo   [4] build LSP server ^& highlighter (bin\zclsp.exe)
+echo   [1] build VM core (build\bin\zy.exe)
+echo   [2] build microcore (build\bin\zym.exe)
+echo   [3] build bootstrap tools (zc0.exe, mkgenome.exe, genmap.exe)
+echo   [4] build LSP server ^& highlighter (build\bin\zclsp.exe)
 echo   [5] build everything
 echo   [6] run Windows test suite (native, LSP, JS, bootstrap)
-echo   [7] run an example on the native VM (bin\zy.exe)
-echo   [8] run an example in the JavaScript VM (node build/js/tinyvm.js)
+echo   [7] run an example on the native VM (build\bin\zy.exe)
+echo   [8] run an example in the JavaScript VM (node build\js\tinyvm.js)
 echo   [9] run a custom .zc source file
-echo   [L] check/highlight .zc with LSP (bin\zclsp.exe)
+echo   [L] check/highlight .zc with LSP (build\bin\zclsp.exe)
 echo   [R] launch the interactive REPL (resident compiler)
-echo   [B] bootstrap and run the full test suite
-echo   [C] clean generated build directories (bin, build)
+echo   [G] rebuild the compiler genome and check the fixpoint
+echo   [C] clean generated output (build)
 echo   [Q] quit
 echo ===============================================================================
-set /p "CHOICE=select an option [1-9, L, R, B, C, Q]: "
+set /p "CHOICE=select an option [1-9, L, R, G, C, Q]: "
 
 if /i "%CHOICE%"=="1" goto :menu_build_core
 if /i "%CHOICE%"=="2" goto :menu_build_micro
@@ -127,7 +152,7 @@ if /i "%CHOICE%"=="8" goto :menu_examples_js
 if /i "%CHOICE%"=="9" goto :menu_run_custom
 if /i "%CHOICE%"=="l" goto :menu_lsp_check
 if /i "%CHOICE%"=="r" goto :menu_repl
-if /i "%CHOICE%"=="b" goto :menu_bootstrap
+if /i "%CHOICE%"=="g" goto :menu_genome
 if /i "%CHOICE%"=="c" goto :menu_clean
 if /i "%CHOICE%"=="q" exit /b 0
 
@@ -141,7 +166,6 @@ REM =========================================================================
 
 :menu_build_core
 echo.
-echo [Building zy.exe]...
 call :build_core
 echo.
 pause
@@ -149,7 +173,6 @@ goto :main_menu
 
 :menu_build_micro
 echo.
-echo [Building zym.exe]...
 call :build_micro
 echo.
 pause
@@ -157,7 +180,6 @@ goto :main_menu
 
 :menu_build_tools
 echo.
-echo [Building tools: zc0.exe, mkgenome.exe, genmap.exe]...
 call :build_tools
 echo.
 pause
@@ -165,7 +187,6 @@ goto :main_menu
 
 :menu_build_lsp
 echo.
-echo [Building zclsp.exe (LSP Server ^& Highlighter)]...
 call :build_lsp
 echo.
 pause
@@ -173,14 +194,7 @@ goto :main_menu
 
 :menu_build_all
 echo.
-echo [Building all components]...
-call :build_core
-if errorlevel 1 goto :build_failed
-call :build_micro
-if errorlevel 1 goto :build_failed
-call :build_tools
-if errorlevel 1 goto :build_failed
-call :build_lsp
+call :build_all
 if errorlevel 1 goto :build_failed
 echo.
 echo [OK] Build complete.
@@ -195,41 +209,23 @@ goto :main_menu
 
 :menu_test
 echo.
-if not exist "bin\zy.exe" (
-    call :build_core
-    if errorlevel 1 goto :build_failed
-)
-if not exist "bin\zym.exe" (
-    call :build_micro
-    if errorlevel 1 goto :build_failed
-)
-echo [Running test suite]...
-powershell -NoProfile -ExecutionPolicy Bypass -File "tests\test_win.ps1"
+call :run_tests
 if errorlevel 1 echo [ERROR] Test suite failed.
 echo.
 pause
 goto :main_menu
 
-:menu_bootstrap
+:menu_genome
 echo.
-echo [Running Bootstrap and Full Test Verification]...
-call :build_tools
+call :build_genome
 if errorlevel 1 goto :build_failed
-if not exist "bin\zy.exe" (
-    call :build_core
-    if errorlevel 1 goto :build_failed
-)
-powershell -NoProfile -ExecutionPolicy Bypass -File "tests\test_win.ps1"
-if errorlevel 1 echo [ERROR] Test suite failed.
 echo.
 pause
 goto :main_menu
 
 :menu_clean
 echo.
-echo [Cleaning build artifacts]...
-rmdir /s /q build bin 2>nul
-echo [OK] Generated bin and build directories removed.
+call :clean
 echo.
 pause
 goto :main_menu
@@ -245,18 +241,15 @@ if not exist "%CUSTOM_FILE%" (
     pause
     goto :main_menu
 )
-
-if not exist "bin\zy.exe" (
-    echo bin\zy.exe not found, building first...
+if not exist "build\bin\zy.exe" (
     call :build_core
     if errorlevel 1 goto :build_failed
 )
-
 echo.
 echo ===============================================================================
 echo Running: %CUSTOM_FILE%
 echo ===============================================================================
-bin\zy.exe < "%CUSTOM_FILE%"
+build\bin\zy.exe < "%CUSTOM_FILE%"
 echo.
 echo ===============================================================================
 pause
@@ -272,18 +265,15 @@ if not exist "%LSP_FILE%" (
     pause
     goto :main_menu
 )
-
-if not exist "bin\zclsp.exe" (
-    echo bin\zclsp.exe not found, building first...
+if not exist "build\bin\zclsp.exe" (
     call :build_lsp
     if errorlevel 1 goto :build_failed
 )
-
 echo.
 echo ===============================================================================
-echo Analyzing with bin\zclsp.exe: %LSP_FILE%
+echo Analyzing with build\bin\zclsp.exe: %LSP_FILE%
 echo ===============================================================================
-bin\zclsp.exe < "%LSP_FILE%"
+build\bin\zclsp.exe < "%LSP_FILE%"
 echo.
 echo ===============================================================================
 pause
@@ -291,8 +281,7 @@ goto :main_menu
 
 :menu_repl
 echo.
-if not exist "bin\zy.exe" (
-    echo bin\zy.exe not found, building first...
+if not exist "build\bin\zy.exe" (
     call :build_core
     if errorlevel 1 goto :build_failed
 )
@@ -302,7 +291,7 @@ echo Each input chunk separated by backtick (`) is compiled and run.
 echo Type expression or function, terminate with ` (or EOF / Ctrl+Z).
 echo Type 'quit;' then backtick or press Ctrl+C to exit.
 echo ===============================================================================
-(type examples\repl.zc & echo ` & more) | bin\zy.exe
+(type examples\repl.zc & echo ` & more) | build\bin\zy.exe
 echo.
 pause
 goto :main_menu
@@ -316,47 +305,24 @@ cls
 echo ===============================================================================
 echo                     Run TinyVM Examples on Native VM (zy.exe)
 echo ===============================================================================
-echo   [1] hello.zc    - Classic "hello, world!"
-echo   [2] fact.zc     - Recursive & iterative factorial computation
-echo   [3] mandel.zc   - Mandelbrot ASCII set using custom enhancement opcode
-echo   [4] primes.zc   - Sieve of Eratosthenes with o3 region compilation
-echo   [5] life.zc     - Conway's Game of Life on a typed torus board
-echo   [6] lists.zc    - Dynamic array with ownership tracking (u, m, d tags)
-echo   [7] typed.zc    - Structs, generic vectors, and reflection
-echo   [8] wiring.zc   - Runtime custom enhancement opcodes demo
-echo   [9] bf.zc       - Brainfuck JIT compiler running inside TinyVM
-echo   [B] Back to main menu
-echo ===============================================================================
+call :example_list
 set /p "EX_CHOICE=Select an example [1-9, B]: "
-
 if /i "%EX_CHOICE%"=="b" goto :main_menu
-set "EX_FILE="
-if "%EX_CHOICE%"=="1" set "EX_FILE=examples\hello.zc"
-if "%EX_CHOICE%"=="2" set "EX_FILE=examples\fact.zc"
-if "%EX_CHOICE%"=="3" set "EX_FILE=examples\mandel.zc"
-if "%EX_CHOICE%"=="4" set "EX_FILE=examples\primes.zc"
-if "%EX_CHOICE%"=="5" set "EX_FILE=examples\life.zc"
-if "%EX_CHOICE%"=="6" set "EX_FILE=examples\lists.zc"
-if "%EX_CHOICE%"=="7" set "EX_FILE=examples\typed.zc"
-if "%EX_CHOICE%"=="8" set "EX_FILE=examples\wiring.zc"
-if "%EX_CHOICE%"=="9" set "EX_FILE=examples\bf.zc"
-
+call :example_file "%EX_CHOICE%"
 if "%EX_FILE%"=="" (
     echo Invalid choice.
     timeout /t 2 >nul
     goto :menu_examples
 )
-
-if not exist "bin\zy.exe" (
+if not exist "build\bin\zy.exe" (
     call :build_core
     if errorlevel 1 goto :build_failed
 )
-
 echo.
 echo ===============================================================================
 echo Running: %EX_FILE%
 echo ===============================================================================
-bin\zy.exe < "%EX_FILE%"
+build\bin\zy.exe < "%EX_FILE%"
 echo.
 echo ===============================================================================
 pause
@@ -367,142 +333,216 @@ cls
 echo ===============================================================================
 echo                 Run TinyVM Examples in JavaScript VM (Node.js)
 echo ===============================================================================
-echo   [1] hello.zc    - Classic "hello, world!"
-echo   [2] fact.zc     - Recursive & iterative factorial computation
-echo   [3] mandel.zc   - Mandelbrot ASCII set using custom enhancement opcode
-echo   [4] primes.zc   - Sieve of Eratosthenes with o3 region compilation
-echo   [5] life.zc     - Conway's Game of Life on a typed torus board
-echo   [6] lists.zc    - Dynamic array with ownership tracking (u, m, d tags)
-echo   [7] typed.zc    - Structs, generic vectors, and reflection
-echo   [8] wiring.zc   - Runtime custom enhancement opcodes demo
-echo   [9] bf.zc       - Brainfuck JIT compiler running inside TinyVM
-echo   [B] Back to main menu
-echo ===============================================================================
-set /p "JS_EX_CHOICE=Select an example [1-9, B]: "
-
-if /i "%JS_EX_CHOICE%"=="b" goto :main_menu
-set "JS_EX_FILE="
-if "%JS_EX_CHOICE%"=="1" set "JS_EX_FILE=examples\hello.zc"
-if "%JS_EX_CHOICE%"=="2" set "JS_EX_FILE=examples\fact.zc"
-if "%JS_EX_CHOICE%"=="3" set "JS_EX_FILE=examples\mandel.zc"
-if "%JS_EX_CHOICE%"=="4" set "JS_EX_FILE=examples\primes.zc"
-if "%JS_EX_CHOICE%"=="5" set "JS_EX_FILE=examples\life.zc"
-if "%JS_EX_CHOICE%"=="6" set "JS_EX_FILE=examples\lists.zc"
-if "%JS_EX_CHOICE%"=="7" set "JS_EX_FILE=examples\typed.zc"
-if "%JS_EX_CHOICE%"=="8" set "JS_EX_FILE=examples\wiring.zc"
-if "%JS_EX_CHOICE%"=="9" set "JS_EX_FILE=examples\bf.zc"
-
-if "%JS_EX_FILE%"=="" (
+call :example_list
+set /p "EX_CHOICE=Select an example [1-9, B]: "
+if /i "%EX_CHOICE%"=="b" goto :main_menu
+call :example_file "%EX_CHOICE%"
+if "%EX_FILE%"=="" (
     echo Invalid choice.
     timeout /t 2 >nul
     goto :menu_examples_js
 )
-
+call :build_js
+if errorlevel 1 goto :build_failed
 echo.
 echo ===============================================================================
-echo Running in JS: %JS_EX_FILE%
+echo Running in JS: %EX_FILE%
 echo ===============================================================================
-node src\js\tinyvm.js "%JS_EX_FILE%"
+node build\js\tinyvm.js "%EX_FILE%"
 echo.
 echo ===============================================================================
 pause
 goto :menu_examples_js
 
+:example_list
+echo   [1] hello.zc    - Classic "hello, world!"
+echo   [2] fact.zc     - Recursive ^& iterative factorial computation
+echo   [3] mandel.zc   - Mandelbrot ASCII set using custom enhancement opcode
+echo   [4] primes.zc   - Sieve of Eratosthenes with o3 region compilation
+echo   [5] life.zc     - Conway's Game of Life on a typed torus board
+echo   [6] lists.zc    - Dynamic array with ownership tracking (u, m, d tags)
+echo   [7] typed.zc    - Structs, generic vectors, and reflection
+echo   [8] wiring.zc   - Runtime custom enhancement opcodes demo
+echo   [9] bf.zc       - Brainfuck compiler running inside TinyVM
+echo   [B] Back to main menu
+echo ===============================================================================
+exit /b 0
+
+:example_file
+set "EX_FILE="
+if "%~1"=="1" set "EX_FILE=examples\hello.zc"
+if "%~1"=="2" set "EX_FILE=examples\fact.zc"
+if "%~1"=="3" set "EX_FILE=examples\mandel.zc"
+if "%~1"=="4" set "EX_FILE=examples\primes.zc"
+if "%~1"=="5" set "EX_FILE=examples\life.zc"
+if "%~1"=="6" set "EX_FILE=examples\lists.zc"
+if "%~1"=="7" set "EX_FILE=examples\typed.zc"
+if "%~1"=="8" set "EX_FILE=examples\wiring.zc"
+if "%~1"=="9" set "EX_FILE=examples\bf.zc"
+exit /b 0
+
 REM =========================================================================
 REM Build Routines
 REM =========================================================================
 
-:build_core
-echo Compiling zy.exe (VM Core with JIT/Interpreter and Enhancements)...
-if not exist "bin" mkdir bin
-"%CC%" -O2 -w -fwrapv -DJTYPE=int src\core\core.c src\core\io_win.c -Isrc/core -o bin\zy.exe
-if errorlevel 1 (echo [ERROR] Failed to build bin\zy.exe.& exit /b 1)
-echo [OK] bin\zy.exe built successfully.
+REM genmap needs no map; the default map comes from it and the zc sources' const blocks
+:build_tools
+if not exist "build\bin" mkdir build\bin
+echo Compiling genmap.exe (memory map generator)...
+"%CC%" -O2 -w -fwrapv src\tools\genmap.c -o build\bin\genmap.exe
+if errorlevel 1 (echo [ERROR] Failed to build build\bin\genmap.exe.& exit /b 1)
+if exist build\core\map rmdir /s /q build\core\map
+if not exist build\core mkdir build\core
+build\bin\genmap.exe --preset default --check -o build\core\map >nul
+if errorlevel 1 (echo [ERROR] The default memory map does not match the sources.& exit /b 1)
+echo Compiling zc0.exe (bootstrap compiler)...
+"%CC%" -O1 -w -fwrapv src\tools\zc0.c -Isrc/core -Ibuild/core/map -o build\bin\zc0.exe
+if errorlevel 1 (echo [ERROR] Failed to build build\bin\zc0.exe.& exit /b 1)
+echo Compiling mkgenome.exe (genome image checker)...
+"%CC%" -O1 -w -fwrapv src\tools\mkgenome.c -Ibuild/core/map -o build\bin\mkgenome.exe
+if errorlevel 1 (echo [ERROR] Failed to build build\bin\mkgenome.exe.& exit /b 1)
+echo [OK] Bootstrap tools built in build\bin.
 exit /b 0
 
-:build_micro
-echo Compiling zym.exe (Portable Microcore)...
-if not exist "bin" mkdir bin
-"%CC%" -O2 -w -fwrapv src\micro\micro.c src\micro\port_win.c -Isrc/core -Isrc/micro -o bin\zym.exe
-if errorlevel 1 (echo [ERROR] Failed to build bin\zym.exe.& exit /b 1)
-echo [OK] bin\zym.exe built successfully.
+REM zc0 compiles the compiler to g0, g0 compiles it to g1, g1 to g2. g1 and g2
+REM must be identical, and g1 becomes build\core\genome.bin.
+:build_genome
+call :build_tools
+if errorlevel 1 exit /b 1
+echo Bootstrapping the compiler genome...
+if not exist build\s0 mkdir build\s0
+if not exist build\s1 mkdir build\s1
+(type src\runtime\rt.zc & type src\core\core.zc & type src\compiler\compiler.zc) | build\bin\zc0.exe > build\s0\g0.bin
+if errorlevel 1 (echo [ERROR] Stage 0 failed.& exit /b 1)
+build\bin\mkgenome.exe < build\s0\g0.bin > build\s0\genome.bin
+if errorlevel 1 (echo [ERROR] Stage 0 did not produce a genome.& exit /b 1)
+"%CC%" -O2 -w -fwrapv -DJTYPE=int src\core\core.c src\core\io_win.c -Isrc/core -Ibuild/core/map --embed-dir=build/s0 -o build\s0\zy0.exe
+if errorlevel 1 (echo [ERROR] Failed to build the stage 0 core.& exit /b 1)
+(type src\tools\build.zc & echo ` & type src\runtime\rt.zc & type src\core\core.zc & type src\compiler\compiler.zc) | build\s0\zy0.exe > build\s1\g1.bin
+build\bin\mkgenome.exe < build\s1\g1.bin > build\s1\genome.bin
+if errorlevel 1 (echo [ERROR] The compiler did not compile itself; its diagnostics are above.& exit /b 1)
+"%CC%" -O2 -w -fwrapv -DJTYPE=int src\core\core.c src\core\io_win.c -Isrc/core -Ibuild/core/map --embed-dir=build/s1 -o build\s1\zy1.exe
+if errorlevel 1 (echo [ERROR] Failed to build the stage 1 core.& exit /b 1)
+(type src\tools\build.zc & echo ` & type src\runtime\rt.zc & type src\core\core.zc & type src\compiler\compiler.zc) | build\s1\zy1.exe > build\s1\g2.bin
+fc /b build\s1\g1.bin build\s1\g2.bin >nul
+if errorlevel 1 (echo [ERROR] Fixpoint failed: the compiler does not compile itself to the same image.& exit /b 1)
+copy /y build\s1\genome.bin build\core\genome.bin >nul
+echo [OK] Fixpoint reached; build\core\genome.bin updated.
 exit /b 0
 
-:build_tools
-if not exist "bin" mkdir bin
-echo Compiling zc0.exe (Bootstrap compiler)...
-"%CC%" -O1 -w -fwrapv src\tools\zc0.c -Isrc/core -o bin\zc0.exe
-if errorlevel 1 (echo [ERROR] Failed to build bin\zc0.exe.& exit /b 1)
-echo Compiling mkgenome.exe (Genome generator)...
-"%CC%" -O1 -w -fwrapv src\tools\mkgenome.c -Isrc/core -o bin\mkgenome.exe
-if errorlevel 1 (echo [ERROR] Failed to build bin\mkgenome.exe.& exit /b 1)
-echo Compiling genmap.exe (Memory map generator)...
-"%CC%" -O2 -w -fwrapv src\tools\genmap.c -Isrc/core -o bin\genmap.exe
-if errorlevel 1 (echo [ERROR] Failed to build bin\genmap.exe.& exit /b 1)
-echo [OK] Bootstrap tools built successfully in bin\.
+:need_genome
+if exist build\core\genome.bin if exist build\core\map\memmap.h exit /b 0
+call :build_genome
+exit /b %errorlevel%
+
+:build_core
+call :need_genome
+if errorlevel 1 exit /b 1
+echo Compiling zy.exe (VM core with the compiler genome)...
+"%CC%" -O2 -w -fwrapv -DJTYPE=int src\core\core.c src\core\io_win.c %COREINC% -o build\bin\zy.exe
+if errorlevel 1 (echo [ERROR] Failed to build build\bin\zy.exe.& exit /b 1)
+echo [OK] build\bin\zy.exe built.
+exit /b 0
+
+:build_micro
+call :need_genome
+if errorlevel 1 exit /b 1
+echo Compiling zym.exe (portable microcore)...
+"%CC%" -O2 -w -fwrapv src\micro\micro.c src\micro\port_win.c %COREINC% -Isrc/micro -o build\bin\zym.exe
+if errorlevel 1 (echo [ERROR] Failed to build build\bin\zym.exe.& exit /b 1)
+echo [OK] build\bin\zym.exe built.
 exit /b 0
 
+REM the language server: the compiler in check mode plus src\lsp\server.zc, on a
+REM map sized to the image (the steps of src/tools/automap.sh lsp with DOCS=1)
 :build_lsp
-echo Compiling zclsp.exe (LSP Server ^& Semantic Highlighter in zc)...
-if not exist "bin" mkdir bin
-if not exist "bin\zc0.exe" (
-    call :build_tools
-    if errorlevel 1 exit /b 1
-)
-if not exist "bin\genmap.exe" (
+if not exist "build\bin\genmap.exe" (
     call :build_tools
     if errorlevel 1 exit /b 1
 )
+echo Compiling zclsp.exe (language server ^& semantic highlighter)...
 if exist build\lsp rmdir /s /q build\lsp
-mkdir build\lsp\src
-if errorlevel 1 (echo [ERROR] Could not create build\lsp.& exit /b 1)
-bin\genmap.exe --preset lsp --grow -o build\lsp\map >nul 2>nul
-if errorlevel 1 (echo [ERROR] Could not generate the initial LSP map.& exit /b 1)
-"%CC%" -O1 -w -fwrapv src\tools\zc0.c -Ibuild\lsp\map -Isrc/core -o build\lsp\zc0.exe
-if errorlevel 1 (echo [ERROR] Could not build the LSP sizing compiler.& exit /b 1)
-(type build\lsp\map\rt.zc & type build\lsp\map\compiler.zc & type src\lsp\server.zc) | build\lsp\zc0.exe > build\lsp\plain.h
-if errorlevel 1 (echo [ERROR] Could not size the LSP genome.& exit /b 1)
-set "GLEN="
-for /f "tokens=3" %%G in ('findstr /b /c:"#define GLEN" build\lsp\plain.h') do set "GLEN=%%G"
-if not defined GLEN (echo [ERROR] Could not read the LSP genome size.& exit /b 1)
-set /a SLOT=(GLEN+4095)/4096*4096
+mkdir build\lsp
+call :lsp_pass "" "" image.bin
+if errorlevel 1 exit /b 1
+call :words build\lsp\image.bin
+set /a SLOT=(WORDS+4095)/4096*4096
 set /a DOCS_WORK=SLOT+65536
-rmdir /s /q build\lsp\map
-bin\genmap.exe --preset lsp --grow --genome %DOCS_WORK% -o build\lsp\map >nul 2>nul
-if errorlevel 1 (echo [ERROR] Could not generate the documentation build map.& exit /b 1)
-"%CC%" -O1 -w -fwrapv -DZC0DOCS src\tools\zc0.c -Ibuild\lsp\map -Isrc/core -o build\lsp\zc0docs.exe
-if errorlevel 1 (echo [ERROR] Could not build the documentation compiler.& exit /b 1)
-(type build\lsp\map\rt.zc & type build\lsp\map\compiler.zc & type src\lsp\server.zc) | build\lsp\zc0docs.exe > build\lsp\docs-first.h
-if errorlevel 1 (echo [ERROR] Could not build the first documentation genome.& exit /b 1)
-set "DOCS_GLEN="
-for /f "tokens=3" %%G in ('findstr /b /c:"#define GLEN" build\lsp\docs-first.h') do set "DOCS_GLEN=%%G"
-if not defined DOCS_GLEN (echo [ERROR] Could not read the documentation genome size.& exit /b 1)
-set /a DOCS_SLOT=(DOCS_GLEN+4095)/4096*4096
-rmdir /s /q build\lsp\map
-bin\genmap.exe --preset lsp --grow --genome %DOCS_SLOT% -o build\lsp\map >nul 2>nul
-if errorlevel 1 (echo [ERROR] Could not generate the sized LSP map.& exit /b 1)
-"%CC%" -O1 -w -fwrapv -DZC0DOCS src\tools\zc0.c -Ibuild\lsp\map -Isrc/core -o build\lsp\zc0docs.exe
-if errorlevel 1 (echo [ERROR] Could not rebuild the documentation compiler.& exit /b 1)
-(type build\lsp\map\rt.zc & type build\lsp\map\compiler.zc & type src\lsp\server.zc) | build\lsp\zc0docs.exe > build\lsp\src\lsp_genome.h
-if errorlevel 1 (echo [ERROR] Could not build the sized documentation genome.& exit /b 1)
-set "FINAL_GLEN="
-for /f "tokens=3" %%G in ('findstr /b /c:"#define GLEN" build\lsp\src\lsp_genome.h') do set "FINAL_GLEN=%%G"
-if not "!FINAL_GLEN!"=="!DOCS_GLEN!" (echo [ERROR] LSP genome changed length after map sizing.& exit /b 1)
-copy /y src\core\core.c build\lsp\src\ >nul
+call :lsp_pass %DOCS_WORK% -DZC0DOCS image.bin
+if errorlevel 1 exit /b 1
+call :words build\lsp\image.bin
+set /a DOCS_SLOT=(WORDS+4095)/4096*4096
+set "DOCS_WORDS=!WORDS!"
+call :lsp_pass %DOCS_SLOT% -DZC0DOCS lsp_genome.bin
+if errorlevel 1 exit /b 1
+call :words build\lsp\lsp_genome.bin
+if not "!WORDS!"=="!DOCS_WORDS!" (echo [ERROR] LSP genome changed length after map sizing.& exit /b 1)
+copy /y build\lsp\map\memmap.h build\lsp\memmap.h >nul
+"%CC%" -O2 -w -fwrapv -DJTYPE=int -DZY_SANDBOX -DUSE_LSP_GENOME src\core\core.c src\core\io_win.c -Isrc/core -Ibuild/lsp --embed-dir=build/lsp -o build\lsp\zclsp.exe
+if errorlevel 1 (echo [ERROR] Failed to build zclsp.exe.& exit /b 1)
+if not exist "build\bin" mkdir build\bin
+copy /y build\lsp\zclsp.exe build\bin\zclsp.exe >nul
+echo [OK] build\bin\zclsp.exe built with !WORDS! words.
+exit /b 0
+
+REM :lsp_pass genome-slot zc0-define output - lay out the lsp map (with that genome
+REM slot, or the preset's own when it is empty) and compile the server image into it
+:lsp_pass
+if exist build\lsp\map rmdir /s /q build\lsp\map
+if "%~1"=="" (
+    build\bin\genmap.exe --preset lsp --grow -o build\lsp\map >nul 2>nul
+) else (
+    build\bin\genmap.exe --preset lsp --grow --genome %~1 -o build\lsp\map >nul 2>nul
+)
+if errorlevel 1 (echo [ERROR] Could not generate the LSP map.& exit /b 1)
+"%CC%" -O1 -w -fwrapv %~2 src\tools\zc0.c -Ibuild/lsp/map -Isrc/core -o build\lsp\zc0.exe
+if errorlevel 1 (echo [ERROR] Could not build the LSP stage 0 compiler.& exit /b 1)
+"%CC%" -O1 -w -fwrapv src\tools\mkgenome.c -Ibuild/lsp/map -o build\lsp\mkgenome.exe
+if errorlevel 1 (echo [ERROR] Could not build the LSP image checker.& exit /b 1)
+(type build\lsp\map\rt.zc & type src\core\core.zc & type build\lsp\map\compiler.zc & type src\lsp\server.zc) | build\lsp\zc0.exe > build\lsp\raw.bin
+if errorlevel 1 (echo [ERROR] Could not compile the LSP image.& exit /b 1)
+build\lsp\mkgenome.exe < build\lsp\raw.bin > build\lsp\%~3
+if errorlevel 1 (echo [ERROR] The LSP image does not match its map.& exit /b 1)
+exit /b 0
+
+REM :words file - WORDS is the file's length in 64-bit words
+:words
+set /a WORDS=%~z1/8
+exit /b 0
+
+REM the javascript vm: layout, genome and the compiled vm in build\js (needs node and tsc)
+:build_js
+call :need_genome
 if errorlevel 1 exit /b 1
-copy /y src\core\io_win.c build\lsp\src\ >nul
+if not exist build\js mkdir build\js
+node src\js\mklayout.js --map build\core\map\memmap.h --out build\js >nul
+if errorlevel 1 (echo [ERROR] Could not write the javascript layout.& exit /b 1)
+copy /y build\core\genome.bin build\js\genome.bin >nul
+call tsc src\js\tinyvm.ts --target es2020 --lib es2020,dom --module commonjs --outDir build\js
+if errorlevel 1 (echo [ERROR] Could not compile the javascript vm; tsc is needed.& exit /b 1)
+exit /b 0
+
+:build_all
+call :build_genome
 if errorlevel 1 exit /b 1
-copy /y src\core\fops.h build\lsp\src\ >nul
+call :build_core
 if errorlevel 1 exit /b 1
-copy /y src\core\bops.h build\lsp\src\ >nul
+call :build_micro
 if errorlevel 1 exit /b 1
-copy /y src\core\stack.h build\lsp\src\ >nul
+call :build_lsp
+exit /b %errorlevel%
+
+:run_tests
+call :build_core
 if errorlevel 1 exit /b 1
-copy /y build\lsp\map\memmap.h build\lsp\src\ >nul
+call :build_micro
 if errorlevel 1 exit /b 1
-"%CC%" -O2 -w -fwrapv -DJTYPE=int -DZY_SANDBOX -DUSE_LSP_GENOME -Ibuild\lsp\src build\lsp\src\core.c build\lsp\src\io_win.c -o bin\zclsp.exe
-if errorlevel 1 (echo [ERROR] Failed to build bin\zclsp.exe.& exit /b 1)
-echo [OK] bin\zclsp.exe built successfully with %FINAL_GLEN% words.
+powershell -NoProfile -ExecutionPolicy Bypass -File "tests\test_win.ps1"
+exit /b %errorlevel%
+
+:clean
+rmdir /s /q build 2>nul
+echo [OK] Generated build directory removed.
 exit /b 0
 
 REM =========================================================================
@@ -514,22 +554,24 @@ set "CMD=%~1"
 set "ARG2=%~2"
 
 if /i "%CMD%"=="build" (
-    if "%ARG2%"=="" goto :cli_build_all
-    if /i "%ARG2%"=="all" goto :cli_build_all
+    if "%ARG2%"=="" ( call :build_all & exit /b !errorlevel! )
+    if /i "%ARG2%"=="all" ( call :build_all & exit /b !errorlevel! )
     if /i "%ARG2%"=="core" ( call :build_core & exit /b !errorlevel! )
     if /i "%ARG2%"=="micro" ( call :build_micro & exit /b !errorlevel! )
     if /i "%ARG2%"=="tools" ( call :build_tools & exit /b !errorlevel! )
     if /i "%ARG2%"=="lsp" ( call :build_lsp & exit /b !errorlevel! )
+    if /i "%ARG2%"=="js" ( call :build_js & exit /b !errorlevel! )
     echo Unknown build target: %ARG2%
     exit /b 1
 )
 
+if /i "%CMD%"=="genome" (
+    call :build_genome
+    exit /b !errorlevel!
+)
+
 if /i "%CMD%"=="test" (
-    call :build_core
-    if errorlevel 1 exit /b 1
-    call :build_micro
-    if errorlevel 1 exit /b 1
-    powershell -NoProfile -ExecutionPolicy Bypass -File "tests\test_win.ps1"
+    call :run_tests
     exit /b !errorlevel!
 )
 
@@ -539,11 +581,11 @@ if /i "%CMD%"=="run" (
         echo Usage: tinyvm.bat run path\to\program.zc
         exit /b 1
     )
-    if not exist "bin\zy.exe" (
+    if not exist "build\bin\zy.exe" (
         call :build_core
         if errorlevel 1 exit /b 1
     )
-    bin\zy.exe < "%SOURCE_ARG%"
+    build\bin\zy.exe < "%SOURCE_ARG%"
     exit /b !errorlevel!
 )
 
@@ -553,11 +595,11 @@ if /i "%CMD%"=="run-micro" (
         echo Usage: tinyvm.bat run-micro path\to\program.zc
         exit /b 1
     )
-    if not exist "bin\zym.exe" (
+    if not exist "build\bin\zym.exe" (
         call :build_micro
         if errorlevel 1 exit /b 1
     )
-    bin\zym.exe < "%SOURCE_ARG%"
+    build\bin\zym.exe < "%SOURCE_ARG%"
     exit /b !errorlevel!
 )
 
@@ -567,7 +609,9 @@ if /i "%CMD%"=="js" (
         echo Usage: tinyvm.bat js path\to\program.zc
         exit /b 1
     )
-    node src\js\tinyvm.js "%SOURCE_ARG%"
+    call :build_js
+    if errorlevel 1 exit /b 1
+    node build\js\tinyvm.js "%SOURCE_ARG%"
     exit /b !errorlevel!
 )
 
@@ -577,62 +621,43 @@ if /i "%CMD%"=="lsp" (
         echo Usage: tinyvm.bat lsp path\to\program.zc
         exit /b 1
     )
-    if not exist "bin\zclsp.exe" (
+    if not exist "build\bin\zclsp.exe" (
         call :build_lsp
         if errorlevel 1 exit /b 1
     )
-    bin\zclsp.exe < "%SOURCE_ARG%"
+    build\bin\zclsp.exe < "%SOURCE_ARG%"
     exit /b !errorlevel!
 )
 
 if /i "%CMD%"=="repl" (
-    if not exist "bin\zy.exe" (
+    if not exist "build\bin\zy.exe" (
         call :build_core
         if errorlevel 1 exit /b 1
     )
-    (type examples\repl.zc & echo ` & more) | bin\zy.exe
+    (type examples\repl.zc & echo ` & more) | build\bin\zy.exe
     exit /b !errorlevel!
 )
 
 if /i "%CMD%"=="clean" (
-    rmdir /s /q build bin 2>nul
-    echo [OK] Generated bin and build directories removed.
+    call :clean
     exit /b 0
 )
 
-if /i "%CMD%"=="help" (
-    goto :show_help
-)
-if /i "%CMD%"=="-h" (
-    goto :show_help
-)
-if /i "%CMD%"=="--help" (
-    goto :show_help
-)
-
 echo Unknown command: %CMD%
 echo.
 exit /b 1
 :show_help
 echo usage: tinyvm.bat [command]
 echo   tinyvm.bat                     launch interactive build ^& run menu
-echo   tinyvm.bat build [all^|core^|micro^|tools^|lsp]
-echo                                  compile TinyVM executables
+echo   tinyvm.bat build [all^|core^|micro^|tools^|lsp^|js]
+echo                                  compile TinyVM executables into build\bin
+echo   tinyvm.bat genome              rebuild build\core\genome.bin and check the fixpoint
 echo   tinyvm.bat run ^<file.zc^>       run a .zc program on VM core (zy.exe)
 echo   tinyvm.bat run-micro ^<file.zc^> run a .zc program on microcore (zym.exe)
 echo   tinyvm.bat js ^<file.zc^>        run a .zc program on the JavaScript VM (node)
 echo   tinyvm.bat lsp ^<file.zc^>       check/highlight a .zc program with zclsp.exe
-echo   tinyvm.bat test                run the full Windows test suite
+echo   tinyvm.bat test                run the Windows test suite
 echo   tinyvm.bat repl                launch the resident compiler REPL
-echo   tinyvm.bat clean               remove generated bin and build directories
+echo   tinyvm.bat clean               remove the generated build directory
+echo the compiler must support c23 #embed: clang 19 or gcc 15 and later.
 exit /b 0
-
-:cli_build_all
-call :build_core
-if errorlevel 1 exit /b 1
-call :build_micro
-if errorlevel 1 exit /b 1
-call :build_tools
-if errorlevel 1 exit /b 1
-call :build_lsp
-exit /b !errorlevel!
diff --git a/tinyvm.sh b/tinyvm.sh
index 7c5ce39..488b1ec 100755
--- a/tinyvm.sh
+++ b/tinyvm.sh
@@ -27,9 +27,9 @@ HELP
 build() {
     case "${1:-all}" in
         all) make ;;
-        core) make bin/zy ;;
-        micro) make bin/zym ;;
-        tools) make bin/zc0 bin/mkgenome bin/genmap ;;
+        core) make build/bin/zy ;;
+        micro) make build/bin/zym ;;
+        tools) make build/bin/zc0 build/bin/mkgenome build/bin/genmap ;;
         lsp) make lsp ;;
         *) printf 'Unknown build target: %s\n' "$1" >&2; return 2 ;;
     esac
@@ -47,9 +47,9 @@ run_file() {
     [[ $# == 2 ]] || { printf 'Usage: tinyvm.sh %s FILE.zc\n' "$mode" >&2; return 2; }
     input=$(source_path "$2") || return
     case $mode in
-        run) exe=bin/zy ;;
-        run-micro) exe=bin/zym ;;
-        lsp) exe=bin/zclsp ;;
+        run) exe=build/bin/zy ;;
+        run-micro) exe=build/bin/zym ;;
+        lsp) exe=build/bin/zclsp ;;
         js) command -v node >/dev/null || { echo 'node.js is required.' >&2; return 1; }; make js || return; node build/js/tinyvm.js "$input"; return ;;
     esac
     make "$exe" || return
@@ -57,9 +57,9 @@ run_file() {
 }
 
 repl() {
-    make bin/zy || return
+    make build/bin/zy || return
     echo 'Enter statements or fn definitions, ending each chunk with a backtick. Ctrl-D exits.'
-    { cat examples/repl.zc; printf '`'; cat; } | bin/zy
+    { cat examples/repl.zc; printf '`'; cat; } | build/bin/zy
 }
 
 dispatch() {