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Subject: Re: IA-64 (Merced) missing bsf & bsr (re: Best way to extract n from 2^n)

Author: Brian Richardson

Date: 07:00:47 09/17/99

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On September 16, 1999 at 17:07:08, J. Wesley Cleveland wrote:

>On September 15, 1999 at 16:57:30, Brian Richardson wrote:
>
>>I have looked at Intel's IA64 architecture guide and can't find these
>>instructions, although there is a popcnt.  Am I missing something?
>
>There is a Compute Zero Index, which would allow you to do it in 3 instructions.

I saw the czx instructions, but they find the first zero byte (or 2 bytes).
How would you use czx to find the first non-zero element?
Also, seems like table lookup would still be needed to find the first/last bit
set?




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