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 <[EMAIL PROTECTED]> 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. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
