Author: Robert Hyatt
Date: 20:49:42 01/18/02
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On January 18, 2002 at 10:44:43, David Rasmussen wrote: >My hashtable implementation has separate tables for white and black, and a part >of each of these tables is depth prioritized. This works ok in general I think. >But I notice that Crafty for one, uses one table, and then inverses the hashkey >in case of probes and stores, when it's black to move. There may be other >implementations as well. > >What are the pros and cons of these approaches, and specifically, why does >Crafty invert the hashkeys in the case of black to move, instead of just hashing >the color into the hashkey? > >/David (who is deparately trying to find a possible hashing bug in Chezzz...) Last question first. Speed. It is cheaper to complement than to load another 64 bit pattern and XOR the two. Saves two memory loads (one 64 bit memory load) when you think about it. I use one table as otherwise with two (one for white one for black) one will often be more utilized than the other, particularly in endgames...
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