X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitcount.h;h=9d25a5e5c1b4d7b7bd19c0bd0cd60234209741a5;hp=b32314d8201ee88db1a6ee5a050d92d398803b86;hb=161c6b025e763d6bcc8339a614be312f2b173437;hpb=d7d2c1b7e31f5b680ebb44e2ffcbfc4bcb2aecfd
diff --git a/src/bitcount.h b/src/bitcount.h
index b32314d8..9d25a5e5 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) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2012 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
@@ -18,79 +18,32 @@
along with this program. If not, see .
*/
-
#if !defined(BITCOUNT_H_INCLUDED)
#define BITCOUNT_H_INCLUDED
+#include
#include "types.h"
-// Select type of intrinsic bit count instruction to use, see
-// README.txt on how to pgo compile with POPCNT support.
-
-#if defined(__INTEL_COMPILER) && defined(USE_POPCNT) // Intel compiler
-
-#include
-
-inline bool cpu_has_popcnt() {
-
- int CPUInfo[4] = {-1};
- __cpuid(CPUInfo, 0x00000001);
- return (CPUInfo[2] >> 23) & 1;
-}
-
-#define POPCNT_INTRINSIC(x) _mm_popcnt_u64(x)
-
-#elif defined(_MSC_VER) && defined(USE_POPCNT) // Microsoft compiler
+enum BitCountType {
+ CNT_64,
+ CNT_64_MAX15,
+ CNT_32,
+ CNT_32_MAX15,
+ CNT_HW_POPCNT
+};
-#include
+/// 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 or
+/// use hardware popcnt instruction when 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;
-inline bool cpu_has_popcnt() {
- int CPUInfo[4] = {-1};
- __cpuid(CPUInfo, 0x00000001);
- return (CPUInfo[2] >> 23) & 1;
-}
-
-#define POPCNT_INTRINSIC(x) __popcnt64(x)
-
-#elif defined(__GNUC__) && defined(USE_POPCNT) // Gcc compiler
-
-inline void __cpuid(unsigned int op,
- unsigned int *eax, unsigned int *ebx,
- unsigned int *ecx, unsigned int *edx)
-{
- *eax = op;
- *ecx = 0;
- __asm__("cpuid" : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx)
- : "0" (*eax), "2" (*ecx));
-}
-
-inline bool cpu_has_popcnt() {
-
- unsigned int eax, ebx, ecx, edx;
- __cpuid(1, &eax, &ebx, &ecx, &edx);
- return (ecx >> 23) & 1;
-}
+/// popcount() counts the number of nonzero bits in a bitboard
+template inline int popcount(Bitboard);
-#define POPCNT_INTRINSIC(x) ({ \
- unsigned long __ret; \
- __asm__("popcnt %1, %0" : "=r" (__ret) : "r" (x)); \
- __ret; })
-
-#else // Safe fallback for unsupported compilers or when USE_POPCNT is disabled
-
-inline bool cpu_has_popcnt() { return false; }
-
-#define POPCNT_INTRINSIC(x) 0
-
-#endif // cpu_has_popcnt() and POPCNT_INTRINSIC() definitions
-
-
-/// Software implementation of bit count functions
-
-#if defined(IS_64BIT)
-
-inline int count_1s(Bitboard b) {
+template<>
+inline int popcount(Bitboard b) {
b -= ((b>>1) & 0x5555555555555555ULL);
b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
@@ -98,16 +51,16 @@ inline int count_1s(Bitboard b) {
return int(b >> 56);
}
-inline int count_1s_max_15(Bitboard b) {
+template<>
+inline int popcount(Bitboard b) {
b -= (b>>1) & 0x5555555555555555ULL;
b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
b *= 0x1111111111111111ULL;
return int(b >> 60);
}
-#else // if !defined(IS_64BIT)
-
-inline int count_1s(Bitboard b) {
+template<>
+inline int popcount(Bitboard b) {
unsigned w = unsigned(b >> 32), v = unsigned(b);
v -= (v >> 1) & 0x55555555; // 0-2 in 2 bits
w -= (w >> 1) & 0x55555555;
@@ -119,7 +72,8 @@ inline int count_1s(Bitboard b) {
return int(v >> 24);
}
-inline int count_1s_max_15(Bitboard b) {
+template<>
+inline int popcount(Bitboard b) {
unsigned w = unsigned(b >> 32), v = unsigned(b);
v -= (v >> 1) & 0x55555555; // 0-2 in 2 bits
w -= (w >> 1) & 0x55555555;
@@ -130,38 +84,29 @@ inline int count_1s_max_15(Bitboard b) {
return int(v >> 28);
}
-#endif // BITCOUNT
-
+template<>
+inline int popcount(Bitboard b) {
-/// count_1s() counts the number of nonzero bits in a bitboard.
-/// If template parameter is true an intrinsic is called, otherwise
-/// we fallback on a software implementation.
+#if !defined(USE_POPCNT)
-template
-inline int count_1s(Bitboard b) {
+ assert(false);
+ return int(b != 0); // Avoid 'b not used' warning
- return UseIntrinsic ? POPCNT_INTRINSIC(b) : count_1s(b);
-}
+#elif defined(_MSC_VER) && defined(__INTEL_COMPILER)
-template
-inline int count_1s_max_15(Bitboard b) {
+ return _mm_popcnt_u64(b);
- return UseIntrinsic ? POPCNT_INTRINSIC(b) : count_1s_max_15(b);
-}
+#elif defined(_MSC_VER)
+ return (int)__popcnt64(b);
-// Global constant initialized at startup that is set to true if
-// CPU on which application runs supports POPCNT intrinsic. Unless
-// USE_POPCNT is not defined.
-const bool CpuHasPOPCNT = cpu_has_popcnt();
+#else
+ unsigned long ret;
+ __asm__("popcnt %1, %0" : "=r" (ret) : "r" (b));
+ return ret;
-// Global constant used to print info about the use of 64 optimized
-// functions to verify that a 64 bit compile has been correctly built.
-#if defined(IS_64BIT)
-const bool CpuHas64BitPath = true;
-#else
-const bool CpuHas64BitPath = false;
#endif
+}
#endif // !defined(BITCOUNT_H_INCLUDED)