Author: Jeremiah Penery
Date: 13:14:57 12/03/02
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On December 03, 2002 at 15:50:15, Russell Reagan wrote: >Is Athlon's bsf instruction significantly slower than that on a P3? I tried this >code against a bsf version on my P3 733 and bsf kills it, big time. I tried all >of these without the feature of resetting the bit. I'm still amazed by the bsf >time though. > >bsf: 4.265 seconds >LSB_64: 42.968 seconds >LastOne(): 39.906 seconds >FirstOne(): 55.125 seconds > >These were posted by Eugene Nalimov. I found them in the archives. BSF/BSR on a P3 are like 1-2 cycle operations. On Athlon, they're more than 10 cycles, plus they block other execution resources.
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