#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
-
-
#include "types.h"
-// Select type of intrinsic bit count instruction to use
+// Select type of intrinsic bit count instruction to use, see
+// README.txt on how to pgo compile with POPCNT support.
-#if defined(_MSC_VER) && defined(_WIN64) // Microsoft compiler
+#if defined(__INTEL_COMPILER) && defined(USE_POPCNT) // Intel compiler
-#include <intrin.h>
+#include <nmmintrin.h>
inline bool cpu_has_popcnt() {
return (CPUInfo[2] >> 23) & 1;
}
-#define POPCNT_INTRINSIC(x) __popcnt64(x)
+#define POPCNT_INTRINSIC(x) _mm_popcnt_u64(x)
-#elif defined(__INTEL_COMPILER) && (defined(__x86_64) || defined(_M_X64)) // Intel compiler
+#elif defined(_MSC_VER) && defined(USE_POPCNT) // Microsoft compiler
-#include <nmmintrin.h>
+#include <intrin.h>
inline bool cpu_has_popcnt() {
return (CPUInfo[2] >> 23) & 1;
}
-#define POPCNT_INTRINSIC(x) _mm_popcnt_u64(x)
+#define POPCNT_INTRINSIC(x) __popcnt64(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) count_1s(x)
+#define POPCNT_INTRINSIC(x) 0
-#endif // cpu_has_popcnt() selection
+#endif // cpu_has_popcnt() and POPCNT_INTRINSIC() definitions
/// Software implementation of bit count functions
}
-// 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.
+// 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