Initial Commit

packages/api-stack/api/api-sandbox-wasm-host-bridge/tests/fixtures/wasm-opcodes.ts

@@ -0,0 +1,112 @@
+/**
+ * Minimal opcode helpers for hand-encoded WASM function bodies. Only the
+ * subset the bridge's fixture WASM needs is implemented — enough to
+ * model a bump allocator, a memcpy loop, packed i64 returns, an
+ * `unreachable` trap, and load/store of static byte ranges out of the
+ * data section.
+ */
+
+import { concat, encodeI32, encodeU32 } from "./leb128.js";
+
+// Value types.
+export const VT_I32 = 0x7f;
+export const VT_I64 = 0x7e;
+
+// Instructions.
+export const OP_UNREACHABLE = 0x00;
+export const OP_NOP = 0x01;
+export const OP_BLOCK = 0x02;
+export const OP_LOOP = 0x03;
+export const OP_BR = 0x0c;
+export const OP_BR_IF = 0x0d;
+export const OP_RETURN = 0x0f;
+export const OP_CALL = 0x10;
+export const OP_DROP = 0x1a;
+export const OP_LOCAL_GET = 0x20;
+export const OP_LOCAL_SET = 0x21;
+export const OP_LOCAL_TEE = 0x22;
+export const OP_GLOBAL_GET = 0x23;
+export const OP_GLOBAL_SET = 0x24;
+export const OP_I32_LOAD = 0x28;
+export const OP_I32_LOAD8_U = 0x2d;
+export const OP_I32_STORE = 0x36;
+export const OP_I32_STORE8 = 0x3a;
+export const OP_I32_CONST = 0x41;
+export const OP_I64_CONST = 0x42;
+export const OP_I32_EQZ = 0x45;
+export const OP_I32_LT_U = 0x49;
+export const OP_I32_ADD = 0x6a;
+export const OP_I32_SUB = 0x6b;
+export const OP_I64_OR = 0x84;
+export const OP_I64_SHL = 0x86;
+export const OP_I64_EXTEND_I32_U = 0xad;
+export const OP_END = 0x0b;
+export const BLOCK_TYPE_EMPTY = 0x40;
+
+export function opI32Const(v: number): Uint8Array {
+    return concat(new Uint8Array([OP_I32_CONST]), encodeI32(v));
+}
+
+export function opLocalGet(idx: number): Uint8Array {
+    return concat(new Uint8Array([OP_LOCAL_GET]), encodeU32(idx));
+}
+
+export function opLocalSet(idx: number): Uint8Array {
+    return concat(new Uint8Array([OP_LOCAL_SET]), encodeU32(idx));
+}
+
+export function opLocalTee(idx: number): Uint8Array {
+    return concat(new Uint8Array([OP_LOCAL_TEE]), encodeU32(idx));
+}
+
+export function opGlobalGet(idx: number): Uint8Array {
+    return concat(new Uint8Array([OP_GLOBAL_GET]), encodeU32(idx));
+}
+
+export function opGlobalSet(idx: number): Uint8Array {
+    return concat(new Uint8Array([OP_GLOBAL_SET]), encodeU32(idx));
+}
+
+/** memarg = align (u32) + offset (u32). */
+function memarg(align = 0, offset = 0): Uint8Array {
+    return concat(encodeU32(align), encodeU32(offset));
+}
+
+export function opI32Load8U(): Uint8Array {
+    return concat(new Uint8Array([OP_I32_LOAD8_U]), memarg(0, 0));
+}
+
+export function opI32Store8(): Uint8Array {
+    return concat(new Uint8Array([OP_I32_STORE8]), memarg(0, 0));
+}
+
+export function opBr(depth: number): Uint8Array {
+    return concat(new Uint8Array([OP_BR]), encodeU32(depth));
+}
+
+export function opBrIf(depth: number): Uint8Array {
+    return concat(new Uint8Array([OP_BR_IF]), encodeU32(depth));
+}
+
+export function opCall(funcIdx: number): Uint8Array {
+    return concat(new Uint8Array([OP_CALL]), encodeU32(funcIdx));
+}
+
+/** Wrap body bytes as a function body: locals + body + end. */
+export function funcBody(
+    locals: ReadonlyArray<{ readonly count: number; readonly type: number }>,
+    body: Uint8Array
+): Uint8Array {
+    const localGroups: Uint8Array[] = [];
+    for (const group of locals) {
+        localGroups.push(
+            concat(encodeU32(group.count), new Uint8Array([group.type]))
+        );
+    }
+    const localsHeader = concat(
+        encodeU32(locals.length),
+        concat(...localGroups)
+    );
+    const inner = concat(localsHeader, body, new Uint8Array([OP_END]));
+    return concat(encodeU32(inner.length), inner);
+}