Author: Robert Hyatt
Date: 12:03:48 06/20/00
Go up one level in this thread
On June 20, 2000 at 14:07:39, Tom Kerrigan wrote: >On June 19, 2000 at 21:32:56, Robert Hyatt wrote: > >>On June 19, 2000 at 20:50:11, John Coffey wrote: >> >>>On June 19, 2000 at 19:48:36, Larry Griffiths wrote: >>> >>>>I have found bitboards to be an even trade-off on my Pentium system. I have to >>>>update about 6 bitboards when a piece moves and this generates a lot of >>>>instructions. I get it back in my IsKingInCheck code so it evens out. I like >>>>to have fast move generation code, but most of my gains have been through >>>>alpha-beta, hash-table, killer-move and movelist ordering etc. >>>> >>>>Larry. >>> >>> >>>Maybe I am too much of a novice, but I don't see yet why I should convert over >>>to bitboards. Is move generation faster? If so, why? My program scans the >>>board and uses simple loops to generate moves. Do you not have to do loops >>>with bitboards? >> >>Not to generate moves, No. You generate all the sliding piece moves with two >>table lookups... > >Hmmm. I do table lookups all over my program, and none of them seem to be >generating any moves... >The fact is that you DO need to loop to generate moves in a bitboard program. >Maybe it's not the same loop, but it's still a loop. > >-Tom Who says so? Ask the Dark Thought guys. Or Slate/Atkin. You only need to loop if you want to take the attack bitmap and turn it into a list of moves. This is not the way _all_ programs operate (chess 4.x, Dark Thought, others, any of which generate a few moves at a time, then take one and search it, without enumerating the other moves.) So loops are something you do (with bitmaps) if you want to, not because you have to. As far as your table lookups not generating any moves, that is a programming issue. Mine do. :)
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