diff options
Diffstat (limited to 'include')
-rw-r--r-- | include/qemu/host-utils.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index 0f688c1c00..de85d282d0 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -228,6 +228,38 @@ static inline int cto64(uint64_t val) } /** + * clrsb32 - count leading redundant sign bits in a 32-bit value. + * @val: The value to search + * + * Returns the number of bits following the sign bit that are equal to it. + * No special cases; output range is [0-31]. + */ +static inline int clrsb32(uint32_t val) +{ +#if QEMU_GNUC_PREREQ(4, 7) + return __builtin_clrsb(val); +#else + return clz32(val ^ ((int32_t)val >> 1)) - 1; +#endif +} + +/** + * clrsb64 - count leading redundant sign bits in a 64-bit value. + * @val: The value to search + * + * Returns the number of bits following the sign bit that are equal to it. + * No special cases; output range is [0-63]. + */ +static inline int clrsb64(uint64_t val) +{ +#if QEMU_GNUC_PREREQ(4, 7) + return __builtin_clrsbll(val); +#else + return clz64(val ^ ((int64_t)val >> 1)) - 1; +#endif +} + +/** * ctpop8 - count the population of one bits in an 8-bit value. * @val: The value to search */ |