Author: Gerd Isenberg
Date: 11:31:14 10/28/02
Go up one level in this thread
On October 26, 2002 at 04:37:06, René Pickhardt wrote: >Hi everybody, >in my actual chess program I use a 2d matrix of short to represent the board. >this is way to slow and uses too much memory so I wanted to change my engine to >bitboards. I found a pretty good link about bit boards >http://www.galahadnet.com/chess/chessprg/bitboard.htm >but I really do not understand how I represent a board by using bitboards. I >understand the idea but I have no idea where to start, does anybody have any >good links about bitboards or good tutorials maybe even with examples >thanks rené Hi rené, the (bit)board representation is distributet on several bitboards (i prefere six piece-bitboards and two bitboards for all pieces for each color). Therefore many bitboard-programs do have a redundant board representation with an array of chars, shorts or ints. Without this, you have to probe several bitboards, doing some conditional jumps or combining the bits with some shift and other logical operations, to get a piece code of one square. The piece-code is required for updating the piece bitboards by doing/undoing moves and even two piece-codes are needed if pieces get captured. Instead of getting the piece-codes via square coordinates from the bitboards or the board array, it is also possible to combine the information of the moving and captured piece (if any) inside the _move_ code. But that requires some effort during the move-generation. On the other hand, traversing bitboards of one kind of target piece for capture generation considering most valuable first may have some (bookholding) advantages. Regards, Gerd
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.