mirror of
https://github.com/sockspls/badfish
synced 2025-04-30 00:33:09 +00:00
134 lines
3.8 KiB
C++
134 lines
3.8 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#if !defined(BITCOUNT_H_INCLUDED)
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#define BITCOUNT_H_INCLUDED
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#include "types.h"
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// Select type of intrinsic bit count instruction to use, see
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// README.txt on how to pgo compile with POPCNT support.
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#if !defined(USE_POPCNT)
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#define POPCNT_INTRINSIC(x) 0
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#elif defined(_MSC_VER)
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#define POPCNT_INTRINSIC(x) (int)__popcnt64(x)
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#elif defined(__GNUC__)
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#define POPCNT_INTRINSIC(x) ({ \
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unsigned long __ret; \
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__asm__("popcnt %1, %0" : "=r" (__ret) : "r" (x)); \
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__ret; })
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#endif
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/// Software implementation of bit count functions
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#if defined(IS_64BIT)
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inline int count_1s(Bitboard b) {
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b -= ((b>>1) & 0x5555555555555555ULL);
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b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
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b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
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b *= 0x0101010101010101ULL;
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return int(b >> 56);
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}
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inline int count_1s_max_15(Bitboard b) {
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b -= (b>>1) & 0x5555555555555555ULL;
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b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
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b *= 0x1111111111111111ULL;
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return int(b >> 60);
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}
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#else // if !defined(IS_64BIT)
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inline int count_1s(Bitboard b) {
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unsigned w = unsigned(b >> 32), v = unsigned(b);
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v -= (v >> 1) & 0x55555555; // 0-2 in 2 bits
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w -= (w >> 1) & 0x55555555;
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v = ((v >> 2) & 0x33333333) + (v & 0x33333333); // 0-4 in 4 bits
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w = ((w >> 2) & 0x33333333) + (w & 0x33333333);
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v = ((v >> 4) + v) & 0x0F0F0F0F; // 0-8 in 8 bits
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v += (((w >> 4) + w) & 0x0F0F0F0F); // 0-16 in 8 bits
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v *= 0x01010101; // mul is fast on amd procs
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return int(v >> 24);
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}
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inline int count_1s_max_15(Bitboard b) {
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unsigned w = unsigned(b >> 32), v = unsigned(b);
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v -= (v >> 1) & 0x55555555; // 0-2 in 2 bits
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w -= (w >> 1) & 0x55555555;
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v = ((v >> 2) & 0x33333333) + (v & 0x33333333); // 0-4 in 4 bits
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w = ((w >> 2) & 0x33333333) + (w & 0x33333333);
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v += w; // 0-8 in 4 bits
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v *= 0x11111111;
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return int(v >> 28);
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}
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#endif // BITCOUNT
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/// count_1s() counts the number of nonzero bits in a bitboard.
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/// If template parameter is true an intrinsic is called, otherwise
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/// we fallback on a software implementation.
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template<bool UseIntrinsic>
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inline int count_1s(Bitboard b) {
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return UseIntrinsic ? POPCNT_INTRINSIC(b) : count_1s(b);
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}
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template<bool UseIntrinsic>
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inline int count_1s_max_15(Bitboard b) {
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return UseIntrinsic ? POPCNT_INTRINSIC(b) : count_1s_max_15(b);
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}
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// Detect hardware POPCNT support
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inline bool cpu_has_popcnt() {
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int CPUInfo[4] = {-1};
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__cpuid(CPUInfo, 0x00000001);
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return (CPUInfo[2] >> 23) & 1;
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}
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// Global constant initialized at startup that is set to true if
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// CPU on which application runs supports POPCNT intrinsic. Unless
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// USE_POPCNT is not defined.
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#if defined(USE_POPCNT)
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const bool CpuHasPOPCNT = cpu_has_popcnt();
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#else
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const bool CpuHasPOPCNT = false;
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#endif
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// Global constant used to print info about the use of 64 optimized
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// functions to verify that a 64 bit compile has been correctly built.
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#if defined(IS_64BIT)
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const bool CpuHas64BitPath = true;
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#else
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const bool CpuHas64BitPath = false;
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#endif
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#endif // !defined(BITCOUNT_H_INCLUDED)
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