Author: Robert Hyatt
Date: 18:29:33 06/21/00
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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...
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