X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fbitcount.h;h=9feed19f9755a94be0022f3e9cf5c891972589d0;hb=766fb9c67da48c696e9444a3a46c531786172256;hp=2300bc96452cef857a819b7ab73b3ddbe8f2cf3e;hpb=9a1d5f0f1d8a12a85b198688d4f1d636a146eb7a;p=stockfish
diff --git a/src/bitcount.h b/src/bitcount.h
index 2300bc96..9feed19f 100644
--- a/src/bitcount.h
+++ b/src/bitcount.h
@@ -1,7 +1,7 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, 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
@@ -18,7 +18,7 @@
along with this program. If not, see .
*/
-#if !defined(BITCOUNT_H_INCLUDED)
+#ifndef BITCOUNT_H_INCLUDED
#define BITCOUNT_H_INCLUDED
#include
@@ -32,14 +32,14 @@ enum BitCountType {
CNT_HW_POPCNT
};
-/// Determine at compile time the best popcount<> specialization according if
-/// platform is 32 or 64 bits, to the maximum number of nonzero bits to count
-/// and if hardware popcnt instruction is available.
+/// 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 nonzero bits in a bitboard
+/// popcount() counts the number of non-zero bits in a bitboard
template inline int popcount(Bitboard);
template<>
@@ -81,7 +81,7 @@ inline int popcount(Bitboard b) {
template<>
inline int popcount(Bitboard b) {
-#if !defined(USE_POPCNT)
+#ifndef USE_POPCNT
assert(false);
return b != 0; // Avoid 'b not used' warning
@@ -96,10 +96,9 @@ inline int popcount(Bitboard b) {
#else
- __asm__("popcnt %1, %0" : "=r" (b) : "r" (b));
- return b;
+ return __builtin_popcountll(b);
#endif
}
-#endif // !defined(BITCOUNT_H_INCLUDED)
+#endif // #ifndef BITCOUNT_H_INCLUDED