Author: Omid David Tabibi
Date: 20:19:45 02/02/04
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On February 02, 2004 at 21:04:46, Russell Reagan wrote: >On February 02, 2004 at 20:06:29, David Rasmussen wrote: > >>Does the Opteron have firstBit, lastBit and popCount instructions? Or at least >>something that makes calculating them easier than on x86-32? >> >>/David > >I have the impression that there is no new magic bullet that will make these >things any easier or faster on the Opteron (well, faster than their 32-bit >counterparts, of course). You might find this post interesting: > >http://chessprogramming.org/cccsearch/ccc.php?art_id=333679 > >Basically, the fastest approaches on 32-bit hardware seemed to be the fastest on >64-bit hardware. I think Eugene's bitscan (or some slight variant) is the >fastest one written in C/C++, Have you compared various C/C++ codes for findFirstBitTrue on 32-bit data? >but if you're willing to do assembly, I think Bob >has some faster stuff. I think Bob's FirstOne() uses bsrq on the Opteron, IIRC, >and he said it was the fastest in real code for Crafty.
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