Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: significant math

Author: Sune Fischer

Date: 02:44:10 11/20/02

Go up one level in this thread


On November 20, 2002 at 05:37:43, Steffan Westcott wrote:

>On November 20, 2002 at 05:05:25, Sune Fischer wrote:
>
>> I believe that "move for move" 0x88 is faster because you don't have to do
>> that extra bit scan to get the square
>
>Which square are you referring to? Source square? Destination square? I may be
>able to help you...

With bitboards (as I'm sure you know) you need a piece of assembler using bsf,
then you need to clear the bit afterwards. This is not needed with 0x88.

ie:
    while (padvances2) {
      to=FirstOne(padvances2);
      *move++=(to+16)|(to<<6)|(pawn<<12);
      Clear(to,padvances2);
    }


>When using bitboards and looking for a pattern instance for a _single_ square,
>think again : You should be looking for pattern instances on _all_ squares
>simulataneously.

Right, I get the idea :)

-S.

>Puzzled,
>Steffan



This page took 0.04 seconds to execute

Last modified: Thu, 07 Jul 11 08:48:38 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.