Author: Walter Faxon
Date: 23:04:20 07/09/03
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On July 09, 2003 at 13:57:06, Gerd Isenberg wrote: [snip] >I don't know the itanium2 instructions set - may be there is some "leading" zero >count or some fast int to float conversion, where you can pass a single isolated >bit as int and get the position from the float exponent. >Anyway there is still Walter Faxon's magic c-routine. > >Regards, >Gerd Hi, Gerd! You may be interested to know that Matt Taylor has developed an "even more magical" c-routine for bit scanning. The xor and folding is replaced by a single multiply then shift. See the thread in the Google group "comp.lang.asm.x86" titled "Bit magic": http://groups.google.com/groups?dq=&hl=en&lr=&ie=UTF-8&threadm=7a851118.0306282017.e9ce4a%40posting.google.com&prev=/groups%3Fdq%3D%26num%3D25%26hl%3Den%26lr%3D%26ie%3DUTF-8%26group%3Dcomp.lang.asm.x86%26start%3D25 I hope he posts the code here soon. -- Walter
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