Author: Eugene Nalimov
Date: 20:54:33 08/17/00
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(1) I already posted that shift by the variable amount have a huge latency on the Itanium, so that there would be no win -- at least no win in terms of clock cycles (yes, function probably would be smaller, but not faster). And you'll need assembly for that -- code I posted is 100% C. (2) I wrote the "original" x86 code (x86.s), after that somebody converted it from Linux-on-x86-asm to everybody-else-on-x86-asm and moved it into vcinline.h. Also, FirstOne()/LastOne() were rewritten, as P6/PII/PIII has fast BSR/BSF instructions, so it's beneficial to use them (on original Pentium they were terrible slow). Eugene On August 17, 2000 at 17:23:45, Brian Richardson wrote: >Eugene: First thank you for your work on EGTBs. Second, thanks for looking >into the IA-64 coding issues. Had you considered the IA-64 instruction that >finds the first non-zero byte in operands of various sizes, and then using that >to index an 8-bit array? Perhaps it is too slow vs your method with may exploit >more parallelism. > >Brian > >PS Did you write vcinline.h for Crafty?
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