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Subject: Re: Bitboard question

Author: Vincent Diepeveen

Date: 08:21:40 05/25/02

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On May 25, 2002 at 11:16:38, Georg v. Zimmermann wrote:

>On May 25, 2002 at 09:49:50, Gian-Carlo Pascutto wrote:
>
>Exactly. And the only other problem are uncovered and covered attacks. But that
>is solvable too.
>Georg

The problems are far greater.

Please try to generate in bitboards mobility with for a bishop
at each square a value in array

   bishopvalues[64];

That's 3 times slower in bitboards than it is in nonbitboards.

Now let's try to get the NUMBER of attackers at a square.

In DIEP this is:

   numberofattackers = Attacks[side][sq] & 15;

In bitboards as crafty uses them you can't even write such
general code!

>
>>On May 25, 2002 at 09:32:58, Russell Reagan wrote:
>>
>>>The problem is that you
>>>have pseudo-attacks.
>>
>>No
>>
>>>Again, this seems like you could calculate pseudo-mobility,
>>
>>No
>>
>>You pick the right bitboard depending on the occupation of
>>a rank/file/diagonal.
>>
>>You need to calculate bitboards in advance for every possible
>>occupation of rank/file/diagonal.
>>
>>--
>>GCP



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