Author: Vincent Diepeveen
Date: 14:34:52 06/22/00
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On June 21, 2000 at 21:29:33, Robert Hyatt wrote: >On June 21, 2000 at 18:47:12, John Coffey wrote: > >>In follow up to Why Bitboards at all? >> >>If bitboards can be used to generate captures, then I assume that these >>are searched first to improve move ordering. Is there any effort to >>determine which capture should be looked at first and do bitboards provide >>other ways to improve move ordering? >> >>John Coffey > >One answer is to do what I do. Use bitboards to produce a move list with >nothing but captures. Then sort the list of captures in any way you want. >Another answer is to use the "belle" approach and use MVV/LVA (most valuable >victim, least valuable attacker) as the ordering strategy and produce the >moves one at a time, as you search them. > > > > > >> >>Being a novice to bitboards I am trying to figure out how to generate a >>capture. If I take a square and then I say take the mask for the moves of >>a bishop for that square, then I have a mask that covers 14 squares. If I & it >>with a mask for my opponent's pieces I have a mask of potential captures >>assuming that no pieces were in the way. So first I would have to come up >>with a mask for legal moves for the bishop before determining the captures? >>This I am not sure how to do, but I am going to try to read up on bitboards. > > > > >Just use the normal approach to produce the bit vector with 1's for _every_ >square that a bishop attacks. AND this with the occupied squares bitmap for >the opponent and you just eliminated all bishop moves except for the ones >that capture opponent pieces... that's a very rude approximation Bob!
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