MIRROR: javascript for 🐜's, a tiny runtime with big ambitions
add wasm demo
+59
+41
examples/demo/build.js
+41
examples/demo/build.js
···
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export function buildWasm({ types, funcs, exports }) {
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const str = s => [s.length, ...Buffer.from(s)];
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const section = (id, data) => [id, data.length, ...data];
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return new Uint8Array([
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0x00,
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0x61,
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0x73,
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0x6d, // magic
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0x01,
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0x00,
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0x00,
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0x00, // version
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...section(0x01, [
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// types
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types.length,
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...types.flatMap(([params, results]) => [0x60, params.length, ...params, results.length, ...results])
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]),
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...section(0x03, [
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// funcs -> type index
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funcs.length,
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...funcs.map((_, i) => i)
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]),
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...section(0x07, [
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// exports
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exports.length,
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...exports.flatMap(([name, kind, idx]) => [...str(name), kind, idx])
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]),
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+
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...section(0x0a, [
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funcs.length,
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...funcs.flatMap(({ locals = [], body }) => {
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const code = [locals.length, ...body, 0x0b];
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return [code.length, ...code];
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})
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])
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]);
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}
+17
examples/demo/wasm.js
+17
examples/demo/wasm.js
···
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import { buildWasm } from './build';
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const i32 = 0x7f;
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const local_get = i => [0x20, i];
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const i32_add = [0x6a];
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const wasmBytes = buildWasm({
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types: [[[i32, i32], [i32]]],
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funcs: [{ body: [...local_get(0), ...local_get(1), ...i32_add] }],
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exports: [['add', 0x00, 0]]
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});
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console.log(`compiled to ${wasmBytes.length} bytes\n`);
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const { instance } = await WebAssembly.instantiate(wasmBytes);
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console.log('add(2, 3) =', instance.exports.add(2, 3));
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console.log('add(100, 200) =', instance.exports.add(100, 200));
+1
src/modules/napi.c
+1
src/modules/napi.c
···
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if (argv) {
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size_t ncopy = requested < info->argc ? requested : info->argc;
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if (ncopy > 0) memcpy(argv, info->argv, ncopy * sizeof(napi_value));
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for (size_t i = ncopy; i < requested; i++) argv[i] = (napi_value)js_mkundef();
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}
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*argc = info->argc;
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}