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    SubjectRe: kernel + gcc 4.1 = several problems
    On Wed, 2007-01-03 at 12:44 +0000, Alan wrote:
    > > > fixed. At that point an i686 kernel would contain i686 instructions and
    > > > actually run on all i686 processors ending all the i586 pain for most
    > > > users and distributions.
    > >
    > > Could you explain why CMOV is pointless now? Are there any benchmarks
    > > proving that?
    > Take a look at the recent ffmpeg bits on the mplayer list for one example
    > I have to hand - P4 cmov is pretty slow. The crypto folks find the same
    > things.

    cmov is effectively the same cost as a compare and jump, in both cases
    the cpu needs to do a prediction, and on a mispredict, restart.

    the reason cmov can make sense is because it's smaller code...

    if you want to mail me at work (you don't), use arjan (at)
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      Last update: 2007-01-03 14:39    [W:0.021 / U:17.528 seconds]
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