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Enable tzcnt intrinsic for GCC when AVX2 is defined

pull/131/head
Jeffrey Walton 2016-04-25 06:24:06 -04:00
parent 9c1c352e98
commit 412a41faa0
1 changed files with 18 additions and 4 deletions
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22
misc.h
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@ -59,6 +59,10 @@
#include <byteswap.h>
#endif
#if defined(__GNUC__) && defined(__AVX2__)
# include <immintrin.h>
#endif
#endif // CRYPTOPP_DOXYGEN_PROCESSING
#if CRYPTOPP_DOXYGEN_PROCESSING
@ -599,10 +603,15 @@ unsigned int BitPrecision(const T &value)
//! \note The function does \a not return 0 if no 1-bits are set because 0 collides with a 1-bit at the 0-th position.
inline unsigned int TrailingZeros(word32 v)
{
// GCC 4.7 and VS2012 provides tzcnt on AVX2/BMI enabled processors
// We don't enable for Microsoft because it requires a runtime check.
// http://msdn.microsoft.com/en-us/library/hh977023%28v=vs.110%29.aspx
assert(v != 0);
#if defined(__GNUC__) && CRYPTOPP_GCC_VERSION >= 30400
#if defined(__GNUC__) && defined(__AVX2__)
return (unsigned int)_tzcnt_u32(v);
#elif defined(__GNUC__) && (CRYPTOPP_GCC_VERSION >= 30400)
return (unsigned int)__builtin_ctz(v);
#elif defined(_MSC_VER) && _MSC_VER >= 1400
#elif defined(_MSC_VER) && (_MSC_VER >= 1400)
unsigned long result;
_BitScanForward(&result, v);
return (unsigned int)result;
@ -625,10 +634,15 @@ inline unsigned int TrailingZeros(word32 v)
//! \note The function does \a not return 0 if no 1-bits are set because 0 collides with a 1-bit at the 0-th position.
inline unsigned int TrailingZeros(word64 v)
{
// GCC 4.7 and VS2012 provides tzcnt on AVX2/BMI enabled processors
// We don't enable for Microsoft because it requires a runtime check.
// http://msdn.microsoft.com/en-us/library/hh977023%28v=vs.110%29.aspx
assert(v != 0);
#if defined(__GNUC__) && CRYPTOPP_GCC_VERSION >= 30400
#if defined(__GNUC__) && defined(__AVX2__)
return (unsigned int)_tzcnt_u64(v);
#elif defined(__GNUC__) && (CRYPTOPP_GCC_VERSION >= 30400)
return (unsigned int)__builtin_ctzll(v);
#elif defined(_MSC_VER) && _MSC_VER >= 1400 && (defined(_M_X64) || defined(_M_IA64))
#elif defined(_MSC_VER) && (_MSC_VER >= 1400) && (defined(_M_X64) || defined(_M_IA64))
unsigned long result;
_BitScanForward64(&result, v);
return (unsigned int)result;