agbcc

Compile C to a Game Boy Advance ARM ELF object in the browser. agbcc (the Thumb cc1) lowers C to ARMv4T Thumb assembly and GNU as assembles it to a relocatable .o — both compiled to WebAssembly.

The .o is byte-identical to the native agbcc + arm-none-eabi-as toolchain for the same input and flags.

Usage

import { compileToObject, preloadAgbcc } from 'agbcc';

preloadAgbcc(); // optional: warm both modules ahead of the first compile

const result = await compileToObject(source, { context });
if (result.ok) {
  result.obj; // Uint8Array — the ARM ELF .o
  result.asm; // the agbcc Thumb assembly
} else {
  result.stderr; // compiler/assembler diagnostics
}

No asset wiring is needed. The emscripten ES modules in dist/ locate their .wasm via import.meta.url, so a bundler (webpack, Vite, etc.) emits dist/agbcc.{mjs,wasm} and dist/as.mjs + dist/as-new.wasm as code-split assets automatically; both modules load lazily on first compile.

compileToObject runs: minimal #define preprocessing (agbcc is cc1, not cpp) → agbcc .i → .s → GNU as .s → .o. A fresh module instance is created per compile (cc1/as are one-shot). The canonical flags are exported as AGBCC_FLAGS / AS_ARGS (also in config.json, importable by Node build steps).

Rebuilding the WebAssembly

source <emsdk>/emsdk_env.sh
sh scripts/build.sh   # -> dist/

See scripts/build.sh for the prerequisites (emsdk, binutils source, and the two source patches the strict wasm-ld linker needs).