Author: Gerd Isenberg
Date: 10:43:38 03/30/04
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On March 30, 2004 at 02:34:21, Slater Wold wrote: >Arasan 7.4 32-bit: > >D12 00:18 @ 729.047 N/sec (starting position) > >Arasan 7.4 64-bit: > >D12 00:17 @ 771,932 N/sec (starting position) > > >64-bit Arasan compiled with: -O2 -Ot -Og -Oi -Gr -GX -Oy -Ob2 -GL >32-bit Arasan would NOT compile on my machine under W2003, so the binary used is >from the Arasan home page. Hi Slater, may you supply a small table with all engines you tested so far? Speedup factor would nice and whether an engine is bitboard based or not ;-) As i saw so far, the 64-bit speedup is not as good as expected. I can't imagine that the signed index issue is that expensive. With similar optimization abilities the 64-bit code should be much faster, simply due to the eight additional registers and (per default? fastcall instead of cdecl or pascal parameter passing). Alignment and Load/Store forewarding stalls are important issues too, but even true for 32-bit code. My guess is, that the 64-bit ms-compiler you use is yet too safe or paranoid with aliasing issues and tends to write locals inside registers to memory permanently. However, it would be interesing to have a look at the generated assembly for some middle sized (20-30 lines c-code) functions with some locals, for 32-bit and 64-bit each. Thanks, Gerd
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