Author: Gerd Isenberg
Date: 07:27:55 07/07/03
Go up one level in this thread
On July 07, 2003 at 10:13:42, Vincent Diepeveen wrote: >On July 07, 2003 at 09:55:26, Gerd Isenberg wrote: > >>On July 07, 2003 at 09:21:17, Jarkko Pesonen wrote: >> >>>In Crafty bitboard function FirstOne gives 12 and LastOne gives 53. >>>Is there fast implementation for LeftOne and RightOne, which >>>would give in below case 33 and 38. >>>C implementation would ne appriciated. >>> >>>---+---+---+---+---+---+---+---+ >>> | | | | | | | | >>>---+---+---+---+---+---+---+---+ >>> | | | | | *P| | | >>>---+---+---+---+---+---+---+---+ >>> | | | | | | | | >>>---+---+---+---+---+---+---+---+ >>> | *P| *P| | | | *P| | >>>---+---+---+---+---+---+---+---+ 0x0080000062000400 >>> | | | | | | | | >>>---+---+---+---+---+---+---+---+ >>> | | | | | | | | >>>---+---+---+---+---+---+---+---+ >>> | | | |*P | | | | >>>---+---+---+---+---+---+---+---+ >>> | | | | | | | | >>>---+---+---+---+---+---+---+---+ >>> >>>thanks in advance >>> >>>Jarkko >> >>Hi Jarkko, >> >>i fear there is no fast LeftOne or RightOne with this bit mapping >>a1=0,h1=7,a2=8,h8=63. Rotating eg. Mirroring files with ranks is a rather time >>comsuming algorithm - unless you use several rotated bitboards with incremental >>update during make/unmake move. > >1 is enough, and further only need is 1 convert and 1 invert array of 64 >squares. I guess Jarkko will do something with pawn bitboards - therefore with rotated i would prefere two pawn bitboards (white and black), or occupied (black/white) and pawns. > >>Regards, >>Gerd
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