diff options
Diffstat (limited to 'py/misc.h')
| -rw-r--r-- | py/misc.h | 33 |
1 files changed, 33 insertions, 0 deletions
@@ -343,13 +343,46 @@ static uint32_t mp_clz(uint32_t x) { return _BitScanReverse(&lz, x) ? (sizeof(x) * 8 - 1) - lz : 0; } +static uint32_t mp_clzl(unsigned long x) { + unsigned long lz = 0; + return _BitScanReverse(&lz, x) ? (sizeof(x) * 8 - 1) - lz : 0; +} + +#ifdef _WIN64 +static uint32_t mp_clzll(unsigned long long x) { + unsigned long lz = 0; + return _BitScanReverse64(&lz, x) ? (sizeof(x) * 8 - 1) - lz : 0; +} +#else +// Microsoft don't ship _BitScanReverse64 on Win32, so emulate it +static uint32_t mp_clzll(unsigned long long x) { + unsigned long h = x >> 32; + return h ? mp_clzl(h) : (mp_clzl(x) + 32); +} +#endif + static uint32_t mp_ctz(uint32_t x) { unsigned long tz = 0; return _BitScanForward(&tz, x) ? tz : 0; } #else #define mp_clz(x) __builtin_clz(x) +#define mp_clzl(x) __builtin_clzl(x) +#define mp_clzll(x) __builtin_clzll(x) #define mp_ctz(x) __builtin_ctz(x) #endif +// mp_int_t can be larger than long, i.e. Windows 64-bit, nan-box variants +static inline uint32_t mp_clz_mpi(mp_int_t x) { + MP_STATIC_ASSERT(sizeof(mp_int_t) == sizeof(long long) + || sizeof(mp_int_t) == sizeof(long)); + + // ugly, but should compile to single intrinsic unless O0 is set + if (sizeof(mp_int_t) == sizeof(long)) { + return mp_clzl(x); + } else { + return mp_clzll(x); + } +} + #endif // MICROPY_INCLUDED_PY_MISC_H |