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Subject: Re: Attack Bitboards

Author: Gerd Isenberg

Date: 06:21:49 10/30/01

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May be you win performance if rank and file of a rook are not occupied or only
occupied by one other man (sliding or noot). But if there are more than one man
on rooks rank or file, the loop becomes very ineffective. The straight foreward
way with four incremental updated occupied bitboards and two 64 Bit reads for
the rook is quite cheap and in average the fastest way without any conditional
jump.

For the four preprocessed xxx_attacks[square][status] arrays it's not necessary
to use all 8 squares on xxx for occupied status, the inner six squares are
enough - so use xxx_attacks[64][64] instead of xxx_attacks[64][256].


Gerd





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