diff options
Diffstat (limited to 'include/msvc_compat')
| -rw-r--r-- | include/msvc_compat/strings.h | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/include/msvc_compat/strings.h b/include/msvc_compat/strings.h index f01ffdd..a3ee250 100644 --- a/include/msvc_compat/strings.h +++ b/include/msvc_compat/strings.h @@ -21,7 +21,37 @@ static __forceinline int ffs(int x) return (ffsl(x)); } +# ifdef _M_X64 +# pragma intrinsic(_BitScanForward64) +# endif + +static __forceinline int ffsll(unsigned __int64 x) +{ + unsigned long i; +#ifdef _M_X64 + if (_BitScanForward64(&i, x)) + return (i + 1); + return (0); +#else +// Fallback for 32-bit build where 64-bit version not available +// assuming little endian + union { + unsigned __int64 ll; + unsigned long l[2]; + } s; + + s.ll = x; + + if (_BitScanForward(&i, s.l[0])) + return (i + 1); + else if(_BitScanForward(&i, s.l[1])) + return (i + 33); + return (0); +#endif +} + #else +# define ffsll(x) __builtin_ffsll(x) # define ffsl(x) __builtin_ffsl(x) # define ffs(x) __builtin_ffs(x) #endif |