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Subject: Re: Bitboards: must I rotate ?

Author: pavel

Date: 12:04:14 05/11/02

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On May 11, 2002 at 09:46:49, Vincent Diepeveen wrote:

>On May 11, 2002 at 05:48:17, Matthias Gemuh wrote:
>
>for attacktables, bitboards isn't the fastest thing.
>
>Bitboards is a tradeoff. You put less information into
>a single 64 bits word. So you can use instructions like AND and OR
>more easily.
>
>However to get attacktables you might want to look at gnuchess 4.0 (not
>5.0 which was raped and rewritten to bitboards for some unknown reason).
>
>Gnuchess is putting more information into a single word for each
>square. The advantage is you can faster work with complex knowledge.
>
>The disadvantage is obviously a slowdown in speed because you use
>more knowledge.

So in short it means, bitboard helps put more information (==more knowledge)in a
single square (64 bits?), if that is what I understand.

I dont know shit about bitboards, if I am not wrong there was an article by Bob
on bitboard (or was it on bitboard rotation?), any idea where I can get hold of
it?

pavs



>
>
>
>>
>>Hi Experts,
>>how much faster can I compute attacks when I rotate ? 5%? 20%? 50%?
>>I don't understand rotation and hope the gain is 1% speed boost :-).
>>Regards,
>>Matthias.



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