HQ attacks for AVX2

mirror of https://github.com/official-stockfish/Stockfish.git synced 2026-07-24 21:57:14 +00:00

passed STC (https://tests.stockfishchess.org/tests/view/6a1157dc818cacc1db0ac172):

LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 29792 W: 7759 L: 7465 D: 14568
Ptnml(0-2): 75, 3206, 8033, 3514, 68

Also passed STC after cleanups https://tests.stockfishchess.org/tests/view/6a121beb818cacc1db0ac35e

vondele's local test:

Result of 100 runs
base (./stockfish.master       ) =    1136025  +/- 2816
test (./stockfish.patch2       ) =    1171370  +/- 2848
diff                             =     +35346  +/- 3275

speedup        = +0.0311
P(speedup > 0) =  1.0000

Basically we just do hyperbola quintessence in parallel. AVX2 doesn't have efficient bit reversal so we only do it for file and bishop attacks, then do rank attacks separately with a lookup table. This LUT is much smaller which is why this seems to be faster than standard magics.

closes https://github.com/official-stockfish/Stockfish/pull/6845

No functional change

This commit is contained in:

anematode

2026-05-25 11:20:24 +02:00

committed by

Joost VandeVondele

parent 41f3557db9

commit 77a8f6ccf3

3 changed files with 143 additions and 7 deletions

									
										src/misc.h
									
		+8
		
												View File
												
				@@ -544,6 +544,14 @@ void move_to_front(std::vector<T>& vec, Predicate pred) {

				    #define sf_unreachable()

				#endif

				#ifdef __GNUC__

				    #define RESTRICT __restrict__

				#elif defined(_MSC_VER)

				    #define RESTRICT __restrict

				#else

				    #define RESTRICT

				#endif

				}  // namespace Stockfish

				template<std::size_t N>