Author: Robert Hyatt
Date: 18:19:45 03/22/99
Go up one level in this thread
On March 22, 1999 at 20:44:59, Greg Lazarou wrote: >Do you really rotate them, or do you maintain the board in straight, 45 degree >(diagonals), 90 degree and 135 degree angles throughout? > >Greg we maintain 4 copies. If I were building a special piece of hardware, I'd obviously rotate as needed by simply gating the right source bits to the right destination bits (this is a straight-forward 1-1 mapping process and would be an 'instant' hardware operation.) > >On March 22, 1999 at 18:29:07, James Robertson wrote: > >>On March 22, 1999 at 17:06:44, Dann Corbit wrote: >> >>>I understand that you can represent a chess board as a rotated bit sets. But my >>>significantly stupid question is "Why rotate them -- what is the advantage?" >> >>To generate moves, you extract 8 adjacent bits from your 64-bit bitboard. This >>works great for rank moves since they are already perfectly lined up. But if you >>want to get file moves, you can't extract every 8th bit, and diagonal moves are >>even worse. If you rotate the bitboard, you can extract file and diagonal moves. >> >>James
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.