Author: Gerd Isenberg
Date: 13:39:53 12/22/05
Go up one level in this thread
On December 22, 2005 at 16:19:58, Zach Wegner wrote: >Hi Gerd, > >Very interesting. I find this line to be particularly elegant: > >> l = (h & -m) | (l & m-1); Hi Zach, yes, simd stuff with mmx/sse2 works that way ;-) > >Unfortunately, in my prototype program it's a tad bit slower (<1%) than the >branch/lookup approach you mention. But, it's only in perft, and I had to add a >couple shifts so that it returns 0x88 coordinates. In a full program where the >lookup tables aren't cached, this method could quite possibly be faster. Do you >think this approach could also be used for the LSB, without adding extra >instructions? It seems you would have to have compares instead of subtracts, or >some NOTs. Of course, should be possible, but i think anding with twos-complement, DeBruijn-multiplication, shift and small L1-lookup is simply faster. Gerd > >Regards, >Zach
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.