arne
/
cryptopp
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Updated to use BLSR intrinsic from SSE4/BMI when available

pull/131/head
Jeffrey Walton 2016-04-26 17:13:15 -04:00
parent ba596654af
commit 1d4967b5fc
1 changed files with 14 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
misc.h
View File

@ -744,6 +744,20 @@ inline bool IsPowerOf2(const T &value)
return value > 0 && (value & (value-1)) == 0; return value > 0 && (value & (value-1)) == 0;
} }
#if defined(__GNUC__) && defined(__BMI__)
template <>
inline bool IsPowerOf2<word32>(const word32 &value)
{
return value > 0 && _blsr_u32(value) == 0;
}
template <>
inline bool IsPowerOf2<word64>(const word64 &value)
{
return value > 0 && _blsr_u64(value) == 0;
}
#endif
//! \brief Tests whether the residue of a value is a power of 2 //! \brief Tests whether the residue of a value is a power of 2
//! \param a the value to test //! \param a the value to test
//! \param b the value to use to reduce \a to its residue //! \param b the value to use to reduce \a to its residue