#if !defined(BITCOUNT_H_INCLUDED)
#define BITCOUNT_H_INCLUDED
-// To disable POPCNT support uncomment following line. You should do it only
-// in PGO compiling to exercise the default fallback path. Don't forget to
-// re-comment the line for the final optimized compile though ;-)
-//#define DISABLE_POPCNT_SUPPORT
+// To enable POPCNT support uncomment USE_POPCNT define. For PGO compile on a Core i7
+// you may want to collect profile data first with USE_POPCNT disabled and then, in a
+// second profiling session, with USE_POPCNT enabled so to exercise both paths. Don't
+// forget to leave USE_POPCNT enabled for the final optimized compile though ;-)
+//#define USE_POPCNT
-#include "bitboard.h"
-
-
-// Select type of software bit count function to use
-
-#if !defined(AUTO_CONFIGURATION) || defined(IS_64BIT)
-
-//#define USE_COMPACT_ROOK_ATTACKS
-//#define USE_32BIT_ATTACKS
-#define USE_FOLDED_BITSCAN
-
-#define BITCOUNT_SWAR_64
-//#define BITCOUNT_SWAR_32
-//#define BITCOUNT_LOOP
-
-#else
-
-#define USE_32BIT_ATTACKS
-#define USE_FOLDED_BITSCAN
-#define BITCOUNT_SWAR_32
-
-#endif
+#include "types.h"
// Select type of intrinsic bit count instruction to use
-#if defined(_MSC_VER) && defined(_WIN64) // Microsoft compiler
+#if defined(_MSC_VER) && defined(IS_64BIT) && defined(USE_POPCNT) // Microsoft compiler
#include <intrin.h>
return (CPUInfo[2] >> 23) & 1;
}
+// Define a dummy template to workaround a compile error if __popcnt64() is not defined.
+//
+// If __popcnt64() is defined in <intrin.h> it will be choosen first due to
+// C++ overload rules that always prefer a function to a template with the same name.
+// If not, we avoid a compile error and because cpu_has_popcnt() should return false,
+// our templetized __popcnt64() is never called anyway.
+template<typename T> unsigned __popcnt64(T) { return 0; } // Is never called
+
#define POPCNT_INTRINSIC(x) __popcnt64(x)
-#elif defined(__INTEL_COMPILER) && (defined(__x86_64) || defined(_M_X64)) // Intel compiler
+#elif defined(__INTEL_COMPILER) && defined(IS_64BIT) && defined(USE_POPCNT) // Intel compiler
#include <nmmintrin.h>
return (CPUInfo[2] >> 23) & 1;
}
+// See comment of __popcnt64<>() few lines above for an explanation.
+template<typename T> unsigned _mm_popcnt_u64(T) { return 0; } // Is never called
+
#define POPCNT_INTRINSIC(x) _mm_popcnt_u64(x)
-#else // Safe fallback for unsupported compilers
+#else // Safe fallback for unsupported compilers or when USE_POPCNT is disabled
inline bool cpu_has_popcnt() { return false; }
-#define POPCNT_INTRINSIC(x) sw_count_1s(x)
+#define POPCNT_INTRINSIC(x) 0
-#endif
+#endif // cpu_has_popcnt() and POPCNT_INTRINSIC() definitions
/// Software implementation of bit count functions
-#if defined(BITCOUNT_LOOP)
+#if defined(IS_64BIT)
-inline int sw_count_1s(Bitboard b) {
- int r;
- for(r = 0; b; r++, b &= b - 1);
- return r;
+inline int count_1s(Bitboard b) {
+ b -= ((b>>1) & 0x5555555555555555ULL);
+ b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
+ b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
+ b *= 0x0101010101010101ULL;
+ return int(b >> 56);
}
-inline int sw_count_1s_max_15(Bitboard b) {
- return count_1s(b);
+inline int count_1s_max_15(Bitboard b) {
+ b -= (b>>1) & 0x5555555555555555ULL;
+ b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
+ b *= 0x1111111111111111ULL;
+ return int(b >> 60);
}
-#elif defined(BITCOUNT_SWAR_32)
+#else // if !defined(IS_64BIT)
-inline int sw_count_1s(Bitboard b) {
+inline int count_1s(Bitboard b) {
unsigned w = unsigned(b >> 32), v = unsigned(b);
v -= (v >> 1) & 0x55555555; // 0-2 in 2 bits
w -= (w >> 1) & 0x55555555;
return int(v >> 24);
}
-inline int sw_count_1s_max_15(Bitboard b) {
+inline int count_1s_max_15(Bitboard b) {
unsigned w = unsigned(b >> 32), v = unsigned(b);
v -= (v >> 1) & 0x55555555; // 0-2 in 2 bits
w -= (w >> 1) & 0x55555555;
return int(v >> 28);
}
-#elif defined(BITCOUNT_SWAR_64)
-
-inline int sw_count_1s(Bitboard b) {
- b -= ((b>>1) & 0x5555555555555555ULL);
- b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
- b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
- b *= 0x0101010101010101ULL;
- return int(b >> 56);
-}
-
-inline int sw_count_1s_max_15(Bitboard b) {
- b -= (b>>1) & 0x5555555555555555ULL;
- b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
- b *= 0x1111111111111111ULL;
- return int(b >> 60);
-}
-
#endif // BITCOUNT
template<bool UseIntrinsic>
inline int count_1s(Bitboard b) {
- return UseIntrinsic ? POPCNT_INTRINSIC(b) : sw_count_1s(b);
+ return UseIntrinsic ? POPCNT_INTRINSIC(b) : count_1s(b);
}
template<bool UseIntrinsic>
inline int count_1s_max_15(Bitboard b) {
- return UseIntrinsic ? POPCNT_INTRINSIC(b) : sw_count_1s_max_15(b);
+ return UseIntrinsic ? POPCNT_INTRINSIC(b) : count_1s_max_15(b);
}
-// Global variable initialized at startup that is set to true if
+// Global constant initialized at startup that is set to true if
// CPU on which application runs supports POPCNT intrinsic. Unless
-// DISABLE_POPCNT_SUPPORT is defined.
-#if defined(DISABLE_POPCNT_SUPPORT)
-const bool CpuHasPOPCNT = false;
-#else
+// USE_POPCNT is not defined.
const bool CpuHasPOPCNT = cpu_has_popcnt();
-#endif
-// Global variable used to print info about the use of 64 optimized
-// functions to verify that a 64bit compile has been correctly built.
-#if defined(BITCOUNT_SWAR_64)
+// 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;
projects / stockfish / blobdiff