Author: Landon Rabern
Date: 00:40:29 01/24/01
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On January 23, 2001 at 16:22:42, Larry Griffiths wrote: >On January 23, 2001 at 15:46:08, Dann Corbit wrote: > >>On January 23, 2001 at 14:41:28, Severi Salminen wrote: >> >>>>I created a GenerateCapturesMoves styled after your Crafty GenMove. >>> >>>What was your previous movegen like? I have not yet watched Crafty's movegen so >>>what modifications did you make to improve your speed? I have also spent a lot >>>time speeding my movegen up and now I'm sometimes faster that Crafty and >>>sometimes not. >>> >>> >>>>Looks like it is worth about 100,000 moves per second in my program. >>>>I do not update hashkeys like your perft does. >>>>I may be able to get a few more moves per second with some tweaking. >>> >>>Indeed you can, but be sure _not_ to make performance comparisons based to perft >>>or perf only. In normal search you should generate 10x (or more)the moves you >>>actually make. So if you make modifications that slow your movemakeing down and >>>speed your movegen up you might get different results in search and perft. Perft >>>will probably indicate that you are slower but in reality you are faster. And a >>>better result in perft might mean worse result in search... :( >> >>Do you use 0x88? >> >>I am experimenting with using a common internal format that is easily translated >>into other formats. I change from bitmaps to 0x88 when the board is dense or >>sparse. > >I am using MMX registers in my program (64-bit :) as they seem to significantly >increase performance when working with bitboards. > >I also re-designed my diagonal bitboards so that pairs of diagonals fit within a >byte. I replaced the SHIFT/AND with... > > _ESI = (unsigned long)fsq;\ > asm lea EDI,bbArray1;\ > asm movzx EAX,bbRankContentsOffset[ESI];\ > asm movzx EBX,bbFileContentsOffset[ESI];\ > asm movzx ECX,bbLDiagContentsOffset[ESI];\ > asm movzx EDX,bbRDiagContentsOffset[ESI];\ > asm movzx EAX,byte ptr [EDI+EAX+bbRankOccupied*8];\ > asm movzx EBX,byte ptr [EDI+EBX+bbFileOccupied*8];\ > asm movzx ECX,byte ptr [EDI+ECX+bbLDiagOccupied*8];\ > asm movzx EDX,byte ptr [EDI+EDX+bbRDiagOccupied*8];\ > >which finds the byte offset in the bitboard using the square number, >then loads the contents of a diagonal into a register using the byte offset. >This seems to have produced a slight increase in performance. How much of a speed increase did you get from using MMX? I got only about a 35% increase. Regards, Landon
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