Author: Gerd Isenberg
Date: 00:41:36 08/27/05
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On August 26, 2005 at 18:12:30, Ed Schröder wrote: >I am no longer up-to-date regarding the newest processors (such as the AMD-64) >and the internal working concerning speed, hence my question: > >Which (similar) code is faster? > > test byte ptr xxx,1 | test byte ptr xxx,1 > je label | mov AL,[ECX] > mov AL,[ECX] | je label > mov BL,[EDX] | mov BL,[EDX] > ... ........ | ... ........ > ... ........ | ... ........ >label: | label: > >Thanks in advance, > >Ed Hi Ed, the conditional jump target is taken from the branch target buffer based on recent targets anyway. I usually prefere your second one, to try to "hide" the latency the zero flag becomes valid (you might also have cache misses of the memory reads as well), but with todays super pipelined processors with huge branch heuristics and out of order execution, i guess that doesn't matter much. Gerd
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