docs: archive the frozen stage code as one compressed tarball

docs/history kept six stages with a full copy of the project under code/,
3.8 mb of sources duplicated from stage to stage and already superseded. store
them as docs/history/code-snapshots.tar.gz, 0.66 mb, and extract one in place
to read it. every stage's notes.md stays browsable, and the index says where the
code went and how to get it back.

the top-level README points at the archive too. its other two links into
docs/history, 21-micro and 35-bench, were notes that were never kept and do not
resolve; the index now records that.

1 files changed, 0 insertions, 83 deletions

diff --git a/docs/history/15-o3/code/tests/o3.zc b/docs/history/15-o3/code/tests/o3.zc
deleted file mode 100644
index 296d1d5..0000000
--- a/docs/history/15-o3/code/tests/o3.zc
+++ /dev/null
@@ -1,83 +0,0 @@
-// o3 regions: every kind of control flow, against the same code without o3
-struct pt { int x; int y; };
-int g = 3;
-int sq(int x) { return x * x; }
-o3 int collatz(int n)
-{
-	int steps = 0;
-	while (n != 1) { if (n % 2 == 0) n = n / 2; else n = 3 * n + 1; steps++; }
-	return steps;
-}
-o3 int ack(int am, int n)
-{
-	if (am == 0) return n + 1;
-	if (n == 0) return ack(am - 1, 1);
-	return ack(am - 1, ack(am, n - 1));
-}
-o3 int many(int a, int b, int c)
-{
-	int dd = a + b, e = b + c, f = c + a, h = dd * e, i2 = e * f, j = f * dd, k = h + i2 + j, l = k / 7;
-	for (int t = 0; t < 5; t++) { dd += t; e -= t; f = f ^ t; l = l + dd * e - f; }
-	return dd + e + f + h + i2 + j + k + l;
-}
-o3 int mix(int n)
-{
-	int acc = 0;
-	for (int i = 0; i < n; i++) {
-		if (i % 3 == 0 && i % 5 == 0) acc += 15;
-		else if (i % 3 == 0 || i > 90) acc += 3;
-		else acc = acc + (i & 1 ? sq(i) : g);
-		switch (i % 4) { case 0: acc += 1; case 1: acc -= 2; default: acc = acc ^ 1; }
-		if (acc > 100000) break;
-		if (i == 7) continue;
-		acc = acc + i / 10 - i % 7 + (i << 2) - (i >> 1);
-	}
-	return acc;
-}
-o3 int dyn(int n)
-{
-	[]int a = new([]int, n);
-	fixed []int f = new(fixed []int, n);
-	int s = 0;
-	for (int i = 0; i < len(a); i++) { a[i] = i * i; f[i] = n - i; }
-	for (int i = 0; i < n; i++) s = s + a[i] * f[i];
-	free(d*a); free(d*f);
-	return s;
-}
-o3 int pts(int n)
-{
-	*pt p = new(pt);
-	int s = 0;
-	p->x = 1; p->y = 2;
-	for (int i = 0; i < n; i++) { p->x = p->x + p->y; p->y = p->x - p->y; s = s + p->x % 1000; }
-	free(d*p);
-	return s;
-}
-o3 int divs(int x)
-{
-	int s = 0;
-	for (int i = -50; i < 50; i++) s = s + (x + i) / 7 + (x + i) % 7 + (x - i) / -3 + i / 16 + i % 16;
-	return s;
-}
-fn main()
-{
-	o3 int lone = 2;
-	let r = 0;
-	lone = lone * 21;
-	o3 {
-		int i = 0, s = 0;
-		while (i < 100) { s = s + collatz(i + 1); i++; }
-		putn(s); putc(' ');
-		putn(lone); putc(' ');
-		lone++;
-	}
-	putn(lone); putc(' ');
-	putn(ack(2, 3)); putc(' ');
-	putn(many(1, 2, 3)); putc(' ');
-	putn(mix(100)); putc(' ');
-	putn(dyn(50)); putc(' ');
-	putn(pts(30)); putc(' ');
-	putn(divs(1000)); putc(' ');
-	putn(divs(-77)); putc(10);
-	return 0;
-}