projects / rustc.git / blame
| Commit | Line | Data |
|---|---|---|
| 970d7e83 LB |
1 | #ifndef strings_h |
| 2 | #define strings_h | |
| 3 | ||
| 4 | /* MSVC doesn't define ffs/ffsl. This dummy strings.h header is provided | |
| 5 | * for both */ | |
| 54a0048b SL |
6 | #ifdef _MSC_VER |
| 7 | # include <intrin.h> | |
| 8 | # pragma intrinsic(_BitScanForward) | |
| 970d7e83 LB |
9 | static __forceinline int ffsl(long x) |
| 10 | { | |
| 11 | unsigned long i; | |
| 12 | ||
| 13 | if (_BitScanForward(&i, x)) | |
| 14 | return (i + 1); | |
| 15 | return (0); | |
| 16 | } | |
| 17 | ||
| 18 | static __forceinline int ffs(int x) | |
| 19 | { | |
| 20 | ||
| 21 | return (ffsl(x)); | |
| 22 | } | |
| 23 | ||
| 54a0048b SL |
24 | # ifdef _M_X64 |
| 25 | # pragma intrinsic(_BitScanForward64) | |
| 26 | # endif | |
| 27 | ||
| 28 | static __forceinline int ffsll(unsigned __int64 x) | |
| 29 | { | |
| 30 | unsigned long i; | |
| 31 | #ifdef _M_X64 | |
| 32 | if (_BitScanForward64(&i, x)) | |
| 33 | return (i + 1); | |
| 34 | return (0); | |
| 35 | #else | |
| 36 | // Fallback for 32-bit build where 64-bit version not available | |
| 37 | // assuming little endian | |
| 38 | union { | |
| 39 | unsigned __int64 ll; | |
| 40 | unsigned long l[2]; | |
| 41 | } s; | |
| 42 | ||
| 43 | s.ll = x; | |
| 44 | ||
| 45 | if (_BitScanForward(&i, s.l[0])) | |
| 46 | return (i + 1); | |
| 47 | else if(_BitScanForward(&i, s.l[1])) | |
| 48 | return (i + 33); | |
| 49 | return (0); | |
| 50 | #endif | |
| 51 | } | |
| 52 | ||
| 53 | #else | |
| 54 | # define ffsll(x) __builtin_ffsll(x) | |
| 55 | # define ffsl(x) __builtin_ffsl(x) | |
| 56 | # define ffs(x) __builtin_ffs(x) | |
| 970d7e83 | 57 | #endif |
| 54a0048b SL |
58 | |
| 59 | #endif /* strings_h */ |