X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=21dc6e44087a36e5c527d0d9a15b78119aa48463;hp=f6f1eba681e6d0030d0e8dccba75565bf9c82070;hb=8fb45caadef67fb2ccc27857c15ade987d9f5e2f;hpb=6c040c821a50475840607ef5f11c270ee21d61da

diff --git a/src/bitboard.h b/src/bitboard.h
index f6f1eba6..21dc6e44 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -2,13 +2,13 @@
   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
@@ -200,14 +200,6 @@ inline Bitboard passed_pawn_mask(Color c, Square s) {
 }
 
 
-/// squares_of_color() returns a bitboard representing all the squares of the
-/// same color of the given one.
-
-inline Bitboard squares_of_color(Square s) {
-  return DarkSquares & s ? DarkSquares : ~DarkSquares;
-}
-
-
 /// aligned() returns true if the squares s1, s2 and s3 are aligned either on a
 /// straight or on a diagonal line.
 
@@ -265,56 +257,65 @@ inline Bitboard attacks_bb(Piece pc, Square s, Bitboard occupied) {
 }
 
 
-/// lsb() and msb() return the least/most significant bit in a non-zero bitboard
+/// popcount() counts the number of non-zero bits in a bitboard
 
-#ifdef USE_BSFQ
+inline int popcount(Bitboard b) {
 
-#  if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
+#ifndef USE_POPCNT
 
-inline Square lsb(Bitboard b) {
-  unsigned long idx;
-  _BitScanForward64(&idx, b);
-  return (Square) idx;
-}
+  extern uint8_t PopCnt16[1 << 16];
+  union { Bitboard bb; uint16_t u[4]; } v = { b };
+  return PopCnt16[v.u[0]] + PopCnt16[v.u[1]] + PopCnt16[v.u[2]] + PopCnt16[v.u[3]];
 
-inline Square msb(Bitboard b) {
-  unsigned long idx;
-  _BitScanReverse64(&idx, b);
-  return (Square) idx;
-}
+#elif defined(_MSC_VER) && defined(__INTEL_COMPILER)
 
-#  elif defined(__arm__)
+  return _mm_popcnt_u64(b);
 
-inline int lsb32(uint32_t v) {
-  __asm__("rbit %0, %1" : "=r"(v) : "r"(v));
-  return __builtin_clz(v);
-}
+#elif defined(_MSC_VER)
 
-inline Square msb(Bitboard b) {
-  return (Square) (63 - __builtin_clzll(b));
+  return (int)__popcnt64(b);
+
+#else // Assumed gcc or compatible compiler
+
+  return __builtin_popcountll(b);
+
+#endif
 }
 
+
+/// lsb() and msb() return the least/most significant bit in a non-zero bitboard
+
+#if defined(__GNUC__)
+
 inline Square lsb(Bitboard b) {
-  return (Square) (uint32_t(b) ? lsb32(uint32_t(b)) : 32 + lsb32(uint32_t(b >> 32)));
+  assert(b);
+  return Square(__builtin_ctzll(b));
 }
 
-#  else // Assumed gcc or compatible compiler
+inline Square msb(Bitboard b) {
+  assert(b);
+  return Square(63 - __builtin_clzll(b));
+}
 
-inline Square lsb(Bitboard b) { // Assembly code by Heinz van Saanen
-  Bitboard idx;
-  __asm__("bsfq %1, %0": "=r"(idx): "rm"(b) );
+#elif defined(_WIN64) && defined(_MSC_VER)
+
+inline Square lsb(Bitboard b) {
+  assert(b);
+  unsigned long idx;
+  _BitScanForward64(&idx, b);
   return (Square) idx;
 }
 
 inline Square msb(Bitboard b) {
-  Bitboard idx;
-  __asm__("bsrq %1, %0": "=r"(idx): "rm"(b) );
+  assert(b);
+  unsigned long idx;
+  _BitScanReverse64(&idx, b);
   return (Square) idx;
 }
 
-#  endif
+#else
 
-#else // ifdef(USE_BSFQ)
+#define NO_BSF // Fallback on software implementation for other cases
 
 Square lsb(Bitboard b);
 Square msb(Bitboard b);