asm.js

• since 2013-03
• source-to-source compiler
• 由 WebAssembly 替代 - 2017+
• asm.js-specific optimizations
  • Chrome 28+
  • Firefox 22+
• limiting language features to improve performance
• "use asm"
• 参考
  • https://en.wikipedia.org/wiki/Asm.js
  • http://asmjs.org/spec/latest/

int f(int i) {
  return i + 1;
}

function f(i) {
  i = i | 0;
  return (i + 1) | 0;
}

const HEAP8 = new Int8Array(e);
const HEAP16 = new Int16Array(e);
const HEAP32 = new Int32Array(e);
const HEAPU8 = new Uint8Array(e);
const HEAPU16 = new Uint16Array(e);
const HEAPU32 = new Uint32Array(e);
const HEAPF32 = new Float32Array(e);
const HEAPF64 = new Float64Array(e);