Author: Bas Hamstra
Date: 06:55:33 12/06/99
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Bob, Do you use the rotated stuff only for movegeneration and not for attack detection? IE if you don't generate your moves bitboard wise, is the rotating stuff obsolete? I ask this, because if I'm not mistaken I saw in the Crafty source that Crafty uses a different approach, ie a BlockMask[F][R] to detect blocked sliding attacks. Regards, Bas Hamstra. On December 06, 1999 at 08:53:12, Robert Hyatt wrote: >On December 05, 1999 at 22:47:06, KarinsDad wrote: > >>On December 05, 1999 at 11:00:19, Robert Hyatt wrote: >> >>[snip] >>> >>> >>>you need 256 entries because that is the number of possible states of any rank >>>or diagonal. >> >>Hmmmm. I'll have to think about this for a while. Seems wasteful on the surface. >> >>> >>>As far as 64 bits goes, within 5 years that is _all_ we will have. Better to >>>plan for the future. It is almost the present. :) >> >>Heck, I cannot even get the present working. ;) >> >>KarinsDad :) > > >Think about this: you want a 64 bit value, which has 1 bits set for each square >the piece in question attacks. For sliding pieces, look at a rank. The rank >can have exactly 256 different states when each square is represented by 1 bit, >with 0=empty and 1=occupied. You grab the rank contents and use that as an >index into this 256 element array to instantly look up the squares the piece >attacks along that rank.
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