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Subject: Re: Efficient Rotated Bitboard Representations

Author: Robert Hyatt

Date: 07:44:25 10/31/98

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On October 31, 1998 at 07:27:43, Bo Persson wrote:

>On October 29, 1998 at 13:20:45, Roberto Waldteufel wrote:
>[snip]
>>Of course, once I started using assembler on the intel CPU, the bsf and bsr
>>instructions were a god-send and I stopped all this nonsense with modular
>>arithmetic....:-)
>>
>>Best wishes,
>>Roberto
>
>I thought these instructions were microcoded and extremely slow on anything
>newer than a 386! When testing on a Pentium, a table lookup was actually much
>faster for me.
>
>
>Bo Persson
>bop@malmo.mail.telia.com


ditto here.  But I only tested this on a P5 (non-mmx) when I started doing this
stuff.  the instructions were grossly slow.  Someone even tried some hand-coded
stuff to help and it was still slower than what I do at present (table lookup).



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