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Subject: Re: huge speedup by using pointers instead of arrays

Author: Michael Henderson

Date: 06:18:51 09/28/04

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On September 28, 2004 at 07:17:00, Roman Hartmann wrote:

>On September 28, 2004 at 06:15:05, Uri Blass wrote:
>
>>On September 28, 2004 at 05:33:46, Roman Hartmann wrote:
>>>Anyway, as I’m not using biboards in my program I was sure my move generator
>>>would be rather slow compared to state of the art bitboard programs.
>>
>>
>>Why?
>>
>>BitBoard is not considered to be faster in generating moves than non bitboards
>>and a lot of commercial programs do not use bitboards.
>>
>>Uri
>
>Well, I had the impression that most of the strong chess engines are using
>bitboards today. I also thought that bitboard programs are in generally faster
>in generating moves than other approaches. But I might be wrong in both cases.

On 32 bit machines, bitboard programs are not fast at generating/making moves
due to breaking up 64 bit commands into two 32 bits commands for every bitboard
operation.  Also there can be a lot more overhead in generating and making
moves.  There is more memory traffic.  Many bitboards must be updated at every
make and unmake move and that is much slower than just clearing and setting a
square in an array.

Michael

>But then I also know only a few non bitboard programs: Phalanx, List (4.61) ...
>
>I don't know what Shredder + Co are actually using but assumed they are using
>bitboards too.
>
>Roman



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