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Subject: Re: questions about dynamically updating attackboards

Author: Sune Fischer

Date: 15:14:25 08/23/03

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On August 23, 2003 at 17:58:16, Uri Blass wrote:

>On August 23, 2003 at 17:29:11, Sune Fischer wrote:
>
>>On August 23, 2003 at 17:12:32, Uri Blass wrote:
>>>
>>>Note that I do not like a piece list of 32 squares because it means that even
>>>after having the attack information I cannot get the information if the square
>>>is attacked by a rook directly and I need to look at the squares of the
>>>attackers to see the type of the piece.
>>
>>There are max 32 pieces on the board, so you just do
>>if (ix_attack_sq[sq] & ix_pc[ROOK]) ...
>>that gives you a 32 bit piece list of rooks (black and white) attacking that
>>square.
>>If you want just white rooks:
>>if (ix_attack_sq[sq] & ix_pc[ROOK] & ix_co[WHITE]) ....
>>and so on.
>>
>>Very elegant and compact, the problem is the incremental update which is very
>>slow.
>>
>>>I like more attack information that give me directly the information if a square
>>>is attacked by a pawn,knight,bishop,...
>>
>>Can it get much faste than that?
>>
>>-S.
>
>I thought about something similiar to Ed's information
>
>bit[square]&3=number of white pawns that attack square
>(bit[square]&12)>>2= number of black pawns that attack the square

Yes you can do that, if you don't need to know where the attacks came from.

It won't be a super accurate SEE, for how do you do x-ray attacks using that?

-S.

>Uri



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