diff options
Diffstat (limited to 'src/osd/eigcc.h')
-rw-r--r-- | src/osd/eigcc.h | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/src/osd/eigcc.h b/src/osd/eigcc.h index 69bbeffde07..2c5bf34ba72 100644 --- a/src/osd/eigcc.h +++ b/src/osd/eigcc.h @@ -55,6 +55,66 @@ inline bool _addu_64x64_co(uint64_t a, uint64_t b, uint64_t &sum) ***************************************************************************/ /*------------------------------------------------- + count_leading_zeros_32 - return the number of + leading zero bits in a 32-bit value +-------------------------------------------------*/ + +#ifndef count_leading_zeros_32 +#define count_leading_zeros_32 _count_leading_zeros_32 +inline uint8_t _count_leading_zeros_32(uint32_t val) +{ + // uses CPU feature if available, otherwise falls back to runtime library call + static_assert(sizeof(val) == sizeof(unsigned), "expected 32-bit unsigned int"); + return uint8_t(unsigned(val ? __builtin_clz(val) : 32)); +} +#endif + + +/*------------------------------------------------- + count_leading_ones_32 - return the number of + leading one bits in a 32-bit value +-------------------------------------------------*/ + +#ifndef count_leading_ones_32 +#define count_leading_ones_32 _count_leading_ones_32 +inline uint8_t _count_leading_ones_32(uint32_t val) +{ + return count_leading_zeros_32(~val); +} +#endif + + +/*------------------------------------------------- + count_leading_zeros_64 - return the number of + leading zero bits in a 64-bit value +-------------------------------------------------*/ + +#ifndef count_leading_zeros_64 +#define count_leading_zeros_64 _count_leading_zeros_64 +inline uint8_t _count_leading_zeros_64(uint64_t val) +{ + // uses CPU feature if available, otherwise falls back to runtime library call + static_assert(sizeof(val) == sizeof(unsigned long long), "expected 64-bit unsigned long long int"); + return uint8_t(unsigned(val ? __builtin_clzll(val) : 64)); +} +#endif + + +/*------------------------------------------------- + count_leading_ones_64 - return the number of + leading one bits in a 64-bit value +-------------------------------------------------*/ + +#ifndef count_leading_ones_64 +#define count_leading_ones_64 _count_leading_ones_64 +inline uint8_t _count_leading_ones_64(uint64_t val) +{ + return count_leading_zeros_64(~val); +} +#endif + + +/*------------------------------------------------- population_count_32 - return the number of one bits in a 32-bit value -------------------------------------------------*/ |