Simplify popcnt

[stockfish] / src / bitcount.h

diff --git a/src/bitcount.h b/src/bitcount.h
deleted file mode 100644 (file)
index 7609da4..0000000
--- a/src/bitcount.h
+++ /dev/null
@@ -1,105 +0,0 @@
-/*
-  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
-  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
-
-  Stockfish is free software: you can redistribute it and/or modify
-  it under the terms of the GNU General Public License as published by
-  the Free Software Foundation, either version 3 of the License, or
-  (at your option) any later version.
-
-  Stockfish is distributed in the hope that it will be useful,
-  but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-  GNU General Public License for more details.
-
-  You should have received a copy of the GNU General Public License
-  along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#ifndef BITCOUNT_H_INCLUDED
-#define BITCOUNT_H_INCLUDED
-
-#include <cassert>
-
-#include "types.h"
-
-enum BitCountType {
-  CNT_64,
-  CNT_64_MAX15,
-  CNT_32,
-  CNT_32_MAX15,
-  CNT_HW_POPCNT
-};
-
-/// Determine at compile time the best popcount<> specialization according to
-/// whether the platform is 32 or 64 bit, the maximum number of non-zero
-/// bits to count and if the hardware popcnt instruction is available.
-const BitCountType Full  = HasPopCnt ? CNT_HW_POPCNT : Is64Bit ? CNT_64       : CNT_32;
-const BitCountType Max15 = HasPopCnt ? CNT_HW_POPCNT : Is64Bit ? CNT_64_MAX15 : CNT_32_MAX15;
-
-
-/// popcount() counts the number of non-zero bits in a bitboard
-template<BitCountType> inline int popcount(Bitboard);
-
-template<>
-inline int popcount<CNT_64>(Bitboard b) {
-  b -=  (b >> 1) & 0x5555555555555555ULL;
-  b  = ((b >> 2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
-  b  = ((b >> 4) + b) & 0x0F0F0F0F0F0F0F0FULL;
-  return (b * 0x0101010101010101ULL) >> 56;
-}
-
-template<>
-inline int popcount<CNT_64_MAX15>(Bitboard b) {
-  b -=  (b >> 1) & 0x5555555555555555ULL;
-  b  = ((b >> 2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
-  return (b * 0x1111111111111111ULL) >> 60;
-}
-
-template<>
-inline int popcount<CNT_32>(Bitboard b) {
-  unsigned w = unsigned(b >> 32), v = unsigned(b);
-  v -=  (v >> 1) & 0x55555555; // 0-2 in 2 bits
-  w -=  (w >> 1) & 0x55555555;
-  v  = ((v >> 2) & 0x33333333) + (v & 0x33333333); // 0-4 in 4 bits
-  w  = ((w >> 2) & 0x33333333) + (w & 0x33333333);
-  v  = ((v >> 4) + v + (w >> 4) + w) & 0x0F0F0F0F;
-  return (v * 0x01010101) >> 24;
-}
-
-template<>
-inline int popcount<CNT_32_MAX15>(Bitboard b) {
-  unsigned w = unsigned(b >> 32), v = unsigned(b);
-  v -=  (v >> 1) & 0x55555555; // 0-2 in 2 bits
-  w -=  (w >> 1) & 0x55555555;
-  v  = ((v >> 2) & 0x33333333) + (v & 0x33333333); // 0-4 in 4 bits
-  w  = ((w >> 2) & 0x33333333) + (w & 0x33333333);
-  return ((v + w) * 0x11111111) >> 28;
-}
-
-template<>
-inline int popcount<CNT_HW_POPCNT>(Bitboard b) {
-
-#ifndef USE_POPCNT
-
-  assert(false);
-  return b != 0; // Avoid 'b not used' warning
-
-#elif defined(_MSC_VER) && defined(__INTEL_COMPILER)
-
-  return _mm_popcnt_u64(b);
-
-#elif defined(_MSC_VER)
-
-  return (int)__popcnt64(b);
-
-#else // Assumed gcc or compatible compiler
-
-  return __builtin_popcountll(b);
-
-#endif
-}
-
-#endif // #ifndef BITCOUNT_H_INCLUDED