Re: [patch 1/13] Qsort

From: Felipe Alfaro Solana
Date: Sat Jan 22 2005 - 23:59:00 EST


On 23 Jan 2005, at 03:39, Andi Kleen wrote:

Felipe Alfaro Solana <lkml@xxxxxxx> 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.

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