Author: Dezhi Zhao
Date: 07:06:47 03/27/03
Go up one level in this thread
On March 27, 2003 at 05:35:10, Uri Blass wrote: >If I want to get rid of the least significant 1 of a BitBoard >I do for a bitboard a >a&=a-1 > >What is the fastest way to get rid of the most significant 1 of >a bitboard? > >Is it slower than a&=a-1 and how much slower? >(it cannot be faster otherwise popcount of crafty could use it). > >Uri To my best knowlege, there is no such well known trick for the most significant bit. Maybe we can send a wish list to Intel and AMD for some new instructions. To seed the list: 1. bsfr : bit scan forward and reset 2. bsrr : bit scan backward and reset requirements: NOT in slow microcode or latency <= 2 cycle:) dzhao
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.