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886Re: [jslint] Re: Save and restore jslint settings

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  • Stefan Weiss
    Sep 4, 2009
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      On 04/09/09 18:10, aseem.kishore@... wrote:
      > For curiosity's sake, I did some testing between bit-shifting and
      > regular math, and it seems bit-shifting is in fact faster for the
      > cases I use.
      >
      > Using these two functions, with i going from 0 to 50000:
      >
      > function pow2BitShifting(i) {
      > var x = 1 << (i % 30);
      > }
      >
      > function pow2RegularMath(i) {
      > var x = Math.pow(2, (i % 30));
      > }

      That's not really a fair comparison. The second function has to do a
      lookup for 'Math', find its 'pow' property, and execute a method call to
      Math.pow.

      So yes, in this case, bit shifting is faster than a call to Math.pow
      with base 2, but that doesn't prove that the bit operations themselves
      are handled efficiently in JS.


      cheers,
      stefan
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