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    SubjectRe: [patch 1/13] Qsort
    On Sun, Jan 23, 2005 at 05:58:00AM +0100, Felipe Alfaro Solana wrote:
    > On 23 Jan 2005, at 03:39, Andi Kleen wrote:
    > >Felipe Alfaro Solana <> writes:
    > >>
    > >>AFAIK, XOR is quite expensive on IA32 when compared to simple MOV
    > >>operatings. Also, since the original patch uses 3 MOVs to perform the
    > >>swapping, and your version uses 3 XOR operations, I don't see any
    > >>gains.
    > >
    > >Both are one cycle latency for register<->register on all x86 cores
    > >I've looked at. What makes you think differently?
    > I thought XOR was more expensie. Anyways, I still don't see any
    > advantage in replacing 3 MOVs with 3 XORs.

    Again, no temporaries needed.

    But I benched it and it was quite a bit slower.

    Mathematics is the supreme nostalgia of our time.
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