Author: Gerd Isenberg
Date: 14:59:48 01/14/03
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On January 14, 2003 at 17:02:09, Sander de Zoete wrote: >Hi Gerd, > >Thanks for your reply. I know about the drawback, but I thought, maybe someone >already found some nice solutions for it. I see. > >It is my first bitboard programme and I didn't want to do the same everyone does >(rotated bitboards). > That's absolutely Ok. It's an really interesting aproach for move generation. >I saw your other postings, I will start to try to understand the code. I don't >have any background in assembly. Is there a website or book you could recommend >me. The fill algorithm like dumb7fill is straight foreward shifting a (or more) bit(s) in the approriate direction (left,right by 1,7,8,9) in an unrolled loop seven times. Before a shift occurs some "and" considers occupied pieces (but not the own one before the first iteration) and a potential wrap from h->a or a->h. The result of each shift is accumulated by oring them into a final attack result register. The more sophisticated Kogge-Stone algorithm introduced to me by Steffan Westcott here in CCC does some really clever parallel prefix computation. I only use several pdfs from amd's developer site: AMD K6 MMX Enhanced Processor AMD 3DNow! Technology Manual TM AMD Extensions to the 3DNow! and MMX Instruction Sets Manual AMD Athlon Processor x86 Code Optimization Guide TM and finally the Hammer Manuals Learning by doing, trying and debugging some sample code, inspecting registers with the debugger... > >Kind regards, >Sander. >PS. It was real fun that this IM used our game in the tournemant as an example, >especially when they where wondering about a really wrong move from Shark. >Obviously I would lose anyhow, but the real reason for this move was that my >processor seemed to have taken a break after overheating, the search quited >after 5 ply or so. Back at home I found out the processor-cooling had melted >down!!! and the computer had to be send back to the manufacturer for repairs. Oups, so sorry, what a mess. Before Shark's Qg6 Isi was not so happy... See You, Gerd
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