Math.round vs hack (v65)

Revision 65 of this benchmark created on

Preparation HTML

<script>
  var somenum = -500 + (Math.random() * 1000);
  var rounded;
  var mround = Math.round;
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
"proper" rounding
rounded = Math.round(somenum);
ready
Hack rounding
rounded = ~~ (0.5 + somenum);
ready
Proper hack rounding
rounded = ~~ (somenum + (somenum > 0 ? .5 : -.5));
ready
Hack with bitwise OR
rounded = (0.5 + somenum) | 0;
ready
Hack with bitwise shift
rounded = (0.5 + somenum) << 0;
ready
xor with 0
rounded = (0.5 + somenum) ^ 0;
ready
bitwise and
rounded = (0.5 + somenum) & 0xffff
ready
bitwise and 64-bit
rounded = (0.5 + somenum) & 0xffffffff
ready
parseInt
rounded = parseInt((0.5 + somenum), 10)
ready
Window-d Math.round
rounded = mround(somenum);
ready

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.