code: function stackAlloc(size) {
    size = size|0;
    var ret = 0;
    ret = STACKTOP;
    STACKTOP = (STACKTOP + size)|0;
    STACKTOP = (STACKTOP + 15)&-16;
  if ((STACKTOP|0) >= (STACK_MAX|0)) abort();
  
    return ret|0;
  }
docs: EMSCRIPTEN_START_FUNCS