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Subject: Re: bitboard routine question

Author: Inmann Werner

Date: 04:13:01 09/18/99

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On September 17, 1999 at 16:16:39, Robert Hyatt wrote:



>
>That is not the way to do it.  There are two good ways to do this.
>
>One is to take each byte and use that as an index into a table that
>gives the first 1 bit set in a byte with that particular subscript.
>The other is to use the assembly code that is included with crafty so
>you can access the BSF/BSR hardware instructions that are _very_ fast.

I tested the different routines (vcinline.c)

AMD K62-450 (100 Million tests)
BSF/BSR  11.640 sec
Lookup    8.900 sec
My Rout. 14.720 sec

Is the AMD BSF/BSR routine slower then the PII one?

Werner





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