Slow asm.js?

asm.js

function murmurhash3(stdlib, foreign, heap) {
  "use asm";

  var int32 = new stdlib.Int32Array(heap);

  function murmurhash3_32(idx, len, seed) {
    idx = idx | 0;
    len = len | 0;
    seed = seed | 0;
    var h = 0, k = 0, i = 0;
    h = seed;
    for (;
      (i | 0) < (len | 0); i = (i + 1) | 0) {
      k = int32[(idx + i) << 2 >> 2] | 0;
      k = ((k * 0xCC9E) << 16) + (k * 0x2D51 | 0) | 0;
      k = (k << 15) | (k >>> 17);
      k = ((k * 0x1B87) << 16) + (k * 0x3593 | 0) | 0;
      h = h ^ k;
      h = (h << 13) | (h >>> 19);
      h = ((h << 2) + h + 0xE6546B64) | 0;
    }
    h = h ^ (len << 2);
    h = h ^ (h >>> 16);
    h = ((h * 0x85EB) << 16) + (h * 0xCA6B | 0) | 0;
    h = h ^ (h >>> 13);
    h = ((h * 0xC2B2) << 16) + (h * 0xAE35 | 0) | 0;
    h = h ^ (h >>> 16);
    return h | 0;
  }

  return {
    hash32: murmurhash3_32,
  };
}

var asmView = new Uint8Array(0x1000);
var asmModule = murmurhash3(window, {}, asmView.buffer);

function prepare(key) {
  for (var i = 0; i < key.length; i++) {
    asmView[i] = key.charCodeAt(i);
  }
  // Ensure the integer is reset.
  var zeroes = 4 - (key.length & 3);
  while (zeroes--) {
    asmView[i++] = 0;
  }
}

function murmur3_asm(key, seed) {
  prepare(key);
  return asmModule.hash32(0, key.length + 3 >> 2, seed);
}