examples: replace snake with mandelbrot (f64 + libc dyn-link demo)

This commit is contained in:
2026-05-11 17:38:25 +09:00
parent 9e383b7ba0
commit 647d3ee05e
5 changed files with 98 additions and 306 deletions

2
.gitignore vendored
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@@ -23,7 +23,7 @@ selfhost/test/*.combined.ww
examples/**/*.o
examples/**/*.s
examples/**/*.combined.ww
examples/snake/snake
examples/mandelbrot/mandelbrot
# Stage-0 binaries under bootstrap/<arch>/. Untracked by default —
# committing them is the v1.0 lock per PLAN.md (the new trust

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@@ -0,0 +1,15 @@
# examples/mandelbrot — built with the ww toolchain only (w6c → w6a → w6l).
#
# `ww build` does the whole pipeline. -l c routes putchar through w6l's
# dynamic linker (PT_INTERP + PT_DYNAMIC + PLT/GOT), so the resulting
# binary maps libc.so.6 at runtime via the system loader. No cc.
WW := $(shell cd ../..; pwd)/out/bin/ww
mandelbrot: mandelbrot.ww
$(WW) build mandelbrot.ww -L /usr/lib -l c
clean:
rm -f mandelbrot mandelbrot.o mandelbrot.s mandelbrot.combined.ww
.PHONY: clean

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@@ -0,0 +1,82 @@
// mandelbrot — ASCII Mandelbrot set, printed via libc.
//
// What this proves:
// 1. ww does f64 arithmetic (mul, add, sub, div) end to end.
// 2. The @symbol FFI mechanism binds write() from libc.so.6.
// 3. w6l's dynamic linker (PT_INTERP + PT_DYNAMIC + PLT/GOT) reaches
// a real .so at runtime — `ldd mandelbrot` shows libc.so.6 as a
// NEEDED entry.
//
// We use libc's `write` (a thin syscall wrapper) rather than `putchar`
// because the runtime here doesn't call __libc_start_main, so stdio
// state stays uninitialised and putchar's buffer is never flushed.
//
// Build: see ./Makefile. No cc — pure ww toolchain.
@symbol("write") fn c_write(fd: i32, buf: *void, n: u64) i64;
def W: i32 = 78;
def H: i32 = 30;
def MAXI: i32 = 80;
// Number of iterations before |z| escapes |z|>2, capped at MAXI.
fn iterate(cr: f64, ci: f64) i32 = {
let zr: f64 = 0.0;
let zi: f64 = 0.0;
let i: i32 = 0;
for (i < MAXI) {
let zr2: f64 = zr * zr;
let zi2: f64 = zi * zi;
if (zr2 + zi2 > 4.0) { return i; };
let nz: f64 = zr2 - zi2 + cr;
zi = (2.0 * zr) * zi + ci;
zr = nz;
i += 1;
};
return MAXI;
};
// Pick an ASCII glyph by escape iteration count. Inside the set
// (n == MAXI) renders as space — the classic look.
fn shade(n: i32) i32 = {
if (n >= MAXI) { return ' ': i32; };
let chars: str = " .:-=+*#%@";
let idx: i32 = (n * chars.len) / MAXI;
if (idx >= chars.len) { idx = chars.len - 1; };
return chars[idx]: i32;
};
export fn main() i32 = {
// Classic Mandelbrot window. The y range is squashed to W/H so
// the picture looks roughly proportional in a terminal cell.
//
// XXX ww's compiler currently emits positive bit patterns for
// negative f64 literals (the unary minus is dropped during
// codegen). As a workaround we build negatives via 0.0 - x.
let z: f64 = 0.0;
let xmin: f64 = z - 2.5;
let xmax: f64 = 1.0;
let ymin: f64 = z - 1.1;
let ymax: f64 = 1.1;
let dx: f64 = (xmax - xmin) / (W: f64);
let dy: f64 = (ymax - ymin) / (H: f64);
// Compose the picture into a row buffer, then flush per row to
// avoid one libc call per character.
let row: [128]u8;
let y: i32 = 0;
for (y < H) {
let ci: f64 = ymin + (y: f64) * dy;
let x: i32 = 0;
for (x < W) {
let cr: f64 = xmin + (x: f64) * dx;
let n: i32 = iterate(cr, ci);
row[x] = (shade(n)): u8;
x += 1;
};
row[W] = 10u8; // '\n'
c_write(1, row.ptr: *void, (W + 1): u64);
y += 1;
};
return 0;
};

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@@ -1,16 +0,0 @@
# examples/snake — built with the ww toolchain only (w6c → w6a → w6l).
#
# `ww build` does the whole pipeline. -l ncurses -l c routes through
# w6l's dynamic linker (PT_INTERP + PT_DYNAMIC + PLT/GOT), so the
# resulting binary maps libncurses.so.6 + libc.so.6 at runtime via
# the system loader. No cc.
WW := $(shell cd ../..; pwd)/out/bin/ww
snake: snake.ww
$(WW) build snake.ww -L /usr/lib -l ncurses -l c
clean:
rm -f snake snake.o snake.s snake.combined.ww
.PHONY: clean

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@@ -1,289 +0,0 @@
// snake — ncurses snake game in ww.
//
// What this proves:
// 1. ww the language can express an interactive program.
// 2. The @symbol FFI mechanism binds to libncurses and libc.
// 3. w6l's new dynamic linker (PT_INTERP + PT_DYNAMIC + PLT/GOT)
// reaches a real .so at runtime — `ldd snake` shows
// libncurses.so.6 and libc.so.6 as NEEDED entries.
//
// Build: see ./Makefile. Pipeline is the ww toolchain (w6c → w6a → w6l)
// with -l ncurses -l c. No cc.
//
// Controls: w/a/s/d to steer, q to quit.
// ---- ncurses bindings -------------------------------------------------
//
// mvaddstr is preferred over mvaddch because chtype's width depends on
// whether ncurses was built with --enable-widec. A NUL-terminated
// 1-byte string sidesteps the question and works on either build.
@symbol("initscr") fn nc_initscr() *void;
@symbol("endwin") fn nc_endwin() i32;
@symbol("cbreak") fn nc_cbreak() i32;
@symbol("noecho") fn nc_noecho() i32;
@symbol("curs_set") fn nc_curs_set(v: i32) i32;
@symbol("timeout") fn nc_timeout(d: i32) void;
@symbol("getch") fn nc_getch() i32;
@symbol("clear") fn nc_clear() i32;
@symbol("refresh") fn nc_refresh() i32;
@symbol("mvaddstr") fn nc_mvaddstr(y: i32, x: i32, s: *u8) i32;
// ---- libc bindings ----------------------------------------------------
@symbol("rand") fn c_rand() i32;
@symbol("srand") fn c_srand(s: u32) void;
@symbol("time") fn c_time(t: *i64) i64;
// ---- board sizing -----------------------------------------------------
def W: i32 = 40;
def H: i32 = 20;
def CAP: i32 = 200; // max snake length, plenty for 40x20
def DIR_UP: i32 = 0;
def DIR_RIGHT: i32 = 1;
def DIR_DOWN: i32 = 2;
def DIR_LEFT: i32 = 3;
def K_W: i32 = 119;
def K_A: i32 = 97;
def K_S: i32 = 115;
def K_D: i32 = 100;
def K_Q: i32 = 113;
// ---- game state -------------------------------------------------------
//
// Snake body lives in a circular buffer of (x, y) pairs addressed by
// (tail, len). Head index is cached as `head`. Arrays live in main's
// frame and are passed in as *i32; struct-with-array codegen still
// segfaults today (probe11.ww).
type state = struct {
head: i32,
tail: i32,
len: i32,
dx: i32,
dy: i32,
dir: i32,
fx: i32,
fy: i32,
score: i32,
dead: bool,
};
fn next_idx(i: i32) i32 = {
let n: i32 = i + 1;
if (n >= CAP) { n = 0; };
return n;
};
fn occupied(s: *state, xs: *i32, ys: *i32, x: i32, y: i32) bool = {
let i: i32 = s.tail;
let k: i32 = 0;
for (k < s.len) {
if (xs[i] == x) {
if (ys[i] == y) { return true; };
};
i = next_idx(i);
k += 1;
};
return false;
};
fn place_food(s: *state, xs: *i32, ys: *i32) void = {
let tries: i32 = 0;
for (tries < 1000) {
let r1: i32 = c_rand();
let r2: i32 = c_rand();
if (r1 < 0) { r1 = -r1; };
if (r2 < 0) { r2 = -r2; };
let x: i32 = r1 % W;
let y: i32 = r2 % H;
if (!occupied(s, xs, ys, x, y)) {
s.fx = x;
s.fy = y;
return;
};
tries += 1;
};
};
fn init_state(s: *state, xs: *i32, ys: *i32) void = {
s.dx = 1;
s.dy = 0;
s.dir = DIR_RIGHT;
s.dead = false;
s.score = 0;
let cx: i32 = W / 2;
let cy: i32 = H / 2;
xs[0] = cx - 2; ys[0] = cy;
xs[1] = cx - 1; ys[1] = cy;
xs[2] = cx; ys[2] = cy;
s.tail = 0;
s.head = 2;
s.len = 3;
place_food(s, xs, ys);
};
fn handle_key(s: *state, k: i32) void = {
if (k == K_W) {
if (s.dir != DIR_DOWN) { s.dx = 0; s.dy = -1; s.dir = DIR_UP; };
};
if (k == K_S) {
if (s.dir != DIR_UP) { s.dx = 0; s.dy = 1; s.dir = DIR_DOWN; };
};
if (k == K_A) {
if (s.dir != DIR_RIGHT) { s.dx = -1; s.dy = 0; s.dir = DIR_LEFT; };
};
if (k == K_D) {
if (s.dir != DIR_LEFT) { s.dx = 1; s.dy = 0; s.dir = DIR_RIGHT; };
};
};
fn step(s: *state, xs: *i32, ys: *i32) void = {
let nx: i32 = xs[s.head] + s.dx;
let ny: i32 = ys[s.head] + s.dy;
if (nx < 0) { s.dead = true; return; };
if (ny < 0) { s.dead = true; return; };
if (nx >= W) { s.dead = true; return; };
if (ny >= H) { s.dead = true; return; };
let grow: bool = false;
if (nx == s.fx) {
if (ny == s.fy) { grow = true; };
};
let scan: i32 = s.len;
if (!grow) { scan = s.len - 1; };
let i: i32 = s.tail;
let k: i32 = 0;
for (k < scan) {
if (xs[i] == nx) {
if (ys[i] == ny) { s.dead = true; return; };
};
i = next_idx(i);
k += 1;
};
let h: i32 = next_idx(s.head);
xs[h] = nx;
ys[h] = ny;
s.head = h;
s.len += 1;
if (grow) {
s.score += 1;
place_food(s, xs, ys);
} else {
s.tail = next_idx(s.tail);
s.len -= 1;
};
};
// itoa: write decimal of n into NUL-terminated buf (room >= 12). Returns
// number of digits written, not counting the NUL.
fn itoa(buf: *u8, n: i32) i32 = {
if (n == 0) {
buf[0] = '0': u8;
buf[1] = 0u8;
return 1;
};
let tmp: [16]u8;
let i: i32 = 0;
let v: i32 = n;
for (v > 0) {
tmp[i] = ((v % 10) + 48): u8;
v = v / 10;
i += 1;
};
let j: i32 = 0;
let cnt: i32 = i;
for (j < cnt) {
i -= 1;
buf[j] = tmp[i];
j += 1;
};
buf[cnt] = 0u8;
return cnt;
};
// ---- rendering --------------------------------------------------------
fn draw_walls() void = {
let x: i32 = 0;
for (x < W + 2) {
nc_mvaddstr(0, x, "#".ptr);
nc_mvaddstr(H + 1, x, "#".ptr);
x += 1;
};
let y: i32 = 0;
for (y < H + 2) {
nc_mvaddstr(y, 0, "#".ptr);
nc_mvaddstr(y, W + 1, "#".ptr);
y += 1;
};
};
fn render(s: *state, xs: *i32, ys: *i32) void = {
nc_clear();
draw_walls();
nc_mvaddstr(s.fy + 1, s.fx + 1, "*".ptr);
let i: i32 = s.tail;
let k: i32 = 0;
for (k < s.len - 1) {
nc_mvaddstr(ys[i] + 1, xs[i] + 1, "o".ptr);
i = next_idx(i);
k += 1;
};
nc_mvaddstr(ys[s.head] + 1, xs[s.head] + 1, "@".ptr);
nc_mvaddstr(H + 2, 0, "score: ".ptr);
let buf: [16]u8;
itoa(buf.ptr, s.score);
nc_mvaddstr(H + 2, 7, buf.ptr);
nc_mvaddstr(H + 2, 14, " (wasd to move, q to quit)".ptr);
nc_refresh();
};
// ---- main -------------------------------------------------------------
export fn main() i32 = {
c_srand((c_time(nil)): u32);
nc_initscr();
nc_cbreak();
nc_noecho();
nc_curs_set(0);
nc_timeout(120);
let s: state;
let xs: [200]i32;
let ys: [200]i32;
init_state(&s, xs.ptr, ys.ptr);
let quit: bool = false;
for (!s.dead) {
render(&s, xs.ptr, ys.ptr);
let k: i32 = nc_getch();
if (k == K_Q) { quit = true; break; };
if (k != -1) { handle_key(&s, k); };
step(&s, xs.ptr, ys.ptr);
};
if (!quit) {
render(&s, xs.ptr, ys.ptr);
nc_mvaddstr(H + 3, 0, "game over - press any key".ptr);
nc_refresh();
nc_timeout(-1);
nc_getch();
};
nc_endwin();
return 0;
};