Author: Vincent Diepeveen
Date: 07:45:05 05/25/02
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On May 25, 2002 at 10:03:02, Daniel Clausen wrote: >On May 25, 2002 at 09:50:27, Vincent Diepeveen wrote: > >>On May 25, 2002 at 09:32:58, Russell Reagan wrote: >> >>A few rude things can be done pretty quick with bitboards >>at 64 bits processors, which is what Bob aimed at a year >>or 10 ago, >>but as soon as you want to evaluate things in detail, then >>please remember what bitboards are: they provide 1 bit of >>info a bitboard about a square. That's very little info. >> > >Nothing prevents a bitboard-based program to use non-bitboard things as well. Eg >I use a simple array 'piece_t square[64]' _additionally_ to all the bitboards, >since it's much faster to use this when you have to find out what piece is on a >certain square. Other bitboard-based programs probably also have this or similar >information stored additionally to the many bitboards. > >Similarly, nothing prevents non-bitboard programs to use bitboards for certain >things. E.g. (Hi Roy! :) using a bitboard for all pawns is quite common, AFAIK. I see nothing in bitboards that would *ever* speed me up with exception of the BITBOARD pawns[2]; Note that in crafty this is BITBOARD whitepawns; BITBOARD blackpawns; That's already too specific code IMHO. Of course writing it out is faster to some extend, but it definitely is going too far already for me! So all the important things get done *nonbitboard* forever in my program. Only when 64 bits processors are really faster than or equal the speed of 32 bits processors (so all general instructions) then it gets interesting to use BITBOARD pawns[2]; What crafty is doing goes too far already IMHO, writing down code specific for every piece. That's way too much spaghetticode IMHO and definitely not a good programming example. >Sargon
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