Author: David Rasmussen
Date: 00:36:08 02/01/01
Go up one level in this thread
On January 31, 2001 at 07:15:59, Dan Newman wrote: >On January 30, 2001 at 06:26:17, David Rasmussen wrote: > >It just means I don't use rotated bitboards. I have a bitboard for each >different piece type (12 bitboards) + occupied square bitboards for each >color (2) + an occupied square bitboard (1). This means make() and undo() >are a bit cheaper since I don't have to update rotated bitboards. Also, >there are a few large data structures (arrays of bitboards) that aren't >needed as well--so fewer memory hits. > >I treat the non-sliding pieces more or less like any other bitboard program, >but for sliding pieces I occasionally resort to scanning the board. I guess >it might be thought of as a sort of hybrid of bitboard and mailbox. > >I suspect (but don't have any hard data) that this is cheaper than doing >rotated bitboards, and it's also much simpler to implement. > >OTOH, I think Bas (Hamstra) may have switched to rotated bitboards and >found them to be faster... > >-Dan. OK, so essentially you don't have any smart way of calculating the attackboard of sliding pieces?? I mean, the normal method of extracting the state of the file, rank or diagonal, and using this to quickly calculate an attackboard, cannot be used in a non-rotated bitboard design. Isn't this just worse in all cases compared to rotated bitboards (except for the simpler design maybe)?
This page took 0.01 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.