while loops!

1 files changed, 111 insertions, 12 deletions

diff --git a/pu2/pu2.c b/pu2/pu2.c
index 7640039..c097873 100644
--- a/pu2/pu2.c
+++ b/pu2/pu2.c
@@ -310,6 +310,7 @@ int ir2_depth = 0;
 
 bool has_jump_warned = false;
 bool has_useless_if_warned = false;
+bool has_false_while_warned = false;
 
 string _ir2(string I, macro_t macros[ 1 << 9 ], label_t labels[ 1 << 10 ], label_delegated_t forward_refs[ 1 << 10 ]) {
     char T;
@@ -366,7 +367,11 @@ string _ir2(string I, macro_t macros[ 1 << 9 ], label_t labels[ 1 << 10 ], label
                 swap();
                 mem_in_a(mem_index);
                 op(sub);
+                swap();
+                imm(mem_index);
                 store();
+
+                continue;
             }
 
             if(*I == '+' && I[1] == '+') { // increment
@@ -377,7 +382,11 @@ string _ir2(string I, macro_t macros[ 1 << 9 ], label_t labels[ 1 << 10 ], label
                 swap();
                 mem_in_a(mem_index);
                 op(add);
+                swap();
+                imm(mem_index);
                 store();
+
+                continue;
             }
 
             char extra_op = '=';
@@ -406,7 +415,7 @@ string _ir2(string I, macro_t macros[ 1 << 9 ], label_t labels[ 1 << 10 ], label
                 } else if (extra_op == '&') {
                     perform_op(and);
                 } else if (extra_op == '!') {
-                    // @1 != @2;
+                    // @1 != @2; (@1 = !@2)
                     mem_in_a(mem2_index);
                     op(not);
                     swap();
@@ -431,20 +440,20 @@ string _ir2(string I, macro_t macros[ 1 << 9 ], label_t labels[ 1 << 10 ], label
                     swap();
                     mem_in_a(mem_index);
                     op(sub);
+                    swap();
+                    imm(mem_index);
                     store();
                 } else if (extra_op == '&') {
                     imm(imm);
                     swap();
                     mem_in_a(mem_index);
                     op(and);
-                    store();
-                } else if (extra_op == '!') {
-                    // @1 != 5;
-                    imm(imm);
-                    op(not);
                     swap();
                     imm(mem_index);
                     store();
+                } else if (extra_op == '!') {
+                    // @1 != 5; (@1 = !5;)
+                    imm_in_mem(mem_index, !imm);
                 }
             }
 
@@ -721,22 +730,23 @@ string _ir2(string I, macro_t macros[ 1 << 9 ], label_t labels[ 1 << 10 ], label
                     int *Code_B = Code;
                     int *Data_B = Data;
 
+                    // completely eliminate code generated in useless if statement
+                    int m2[S/4];
+                    Data = Code = m2;
+
                     // get new I location
                     string new_I = _ir2(I, macros, labels, forward_refs);
                     I = new_I;
                     // restore values
                     Code = Code_B;
                     Data = Data_B;
-
-                    continue;
-                }
-
-                else {
+                } else {
                     // just... i mean, i guess run the code..?
                     string new_I = _ir2(I, macros, labels, forward_refs);
                     I = new_I;
-                    continue;
                 }
+
+                continue;
             }
 
             bool was_negated = false;
@@ -769,6 +779,95 @@ string _ir2(string I, macro_t macros[ 1 << 9 ], label_t labels[ 1 << 10 ], label
             continue;
         }
 
+        else if (strncmp("while", I, 5) == 0 && !isalnum(I[5])) {
+            I += 5;
+            space; checkskip('(', "expected open paren for while loop"); space;
+            ir2_depth++;
+
+            if (isdigit(*I)) {
+                int value = strtol(I, &I, 10); space;
+
+                checkskip(')', "expected closing paren after while loop argument"); space;
+                checkskip('{', "expected opening bracket for while loop body"); space;
+
+                if (!value) {
+                    // non-running while loop
+
+                    if(!has_false_while_warned) {
+                        has_false_while_warned = true;
+                        printf("warn: dead code inside while loop\n");
+                    }
+
+                    // just skip over everything inside
+
+                    int *Code_B = Code;
+                    int *Data_B = Data;
+
+                    // completely eliminate code generated in useless while loop
+                    int m2[S/4];
+                    Data = Code = m2;
+
+                    // get new I location
+                    string new_I = _ir2(I, macros, labels, forward_refs);
+                    I = new_I;
+                    // restore values
+                    Code = Code_B;
+                    Data = Data_B;
+                } else {
+                    // run forever!
+
+                    int start = Code - m;
+                    
+                    string new_I = _ir2(I, macros, labels, forward_refs);
+                    I = new_I;
+
+                    imm_in_mem(7, start); // always jump back to the start
+                }
+
+                continue;
+            }
+
+            bool was_negated = false;
+            if (*I == '!') {
+                was_negated = true;
+                I++; space;
+            }
+
+            checkskip('@', "expected memory address for while loop expression (hint: only simple conditions are supported)");
+            if (!isdigit(*I)) run_err(I, "expected memory index");
+            int mem_index = strtol(I, &I, 10); space; 
+            checkskip(')', "expected closing paren after while loop condition"); space;
+            checkskip('{', "expected opening bracket for while loop body"); space;
+            
+            mem_in_a(mem_index);
+            if (!was_negated) op(not);
+            op(a2u);
+            imm(0xDEAD10C4); // DEADLOCK - placeholder for the patchback
+            int* patchback = Code - 1;
+            swap();
+            imm(7);
+            op(str);
+
+            int start_index = Code - m;
+
+            // handle the code stuff
+            string new_I = _ir2(I, macros, labels, forward_refs);
+            I = new_I;
+
+            *patchback = Code - m; // patch the jump instruction
+
+            // check the condition and jump back if true
+            mem_in_a(mem_index);
+            if (was_negated) op(not);
+            op(a2u);
+            imm(start_index);
+            swap();
+            imm(7);
+            op(str);
+
+            continue;
+        }
+
         // macro call, maybe?
         else if (isalpha(*I)) {
             string old_I = I;