From: Jim Weirich <jim@...>
Date: 2006-04-09T05:52:51+09:00
Subject: Re: Ruby: shift right operator (>>) does not work correctly

Vitalie Lazu wrote:
> It seems to be a bug with >> operator:
> 
> 4653896912 >> 13 should be 43814 like it is in java or php, but not
> 568102.
> 
> Tested with ruby 1.8.2 in windows xp and freebsd.
> 
> any related issues to this subject?
> 
> Best regards,
> Vitalie

  > Math.log(4653896912) / Math.log(2)
  => 32.1157921080915

There you have it, the number 4653896912 cannot be represented in 32 
bits (it needs 33 bits, 34 if you add a sign bit).  Java is truncating 
the value:

  > (4653896912 & 0xffffffff)
  => 358929616
  > 358929616 >> 13
  => 43814

-- Jim Weirich

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