diff options
| -rw-r--r-- | include/qemu/host-utils.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index 3ce62bf..d3b4dce 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -108,6 +108,36 @@ static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c) #endif /** + * clz8 - count leading zeros in a 8-bit value. + * @val: The value to search + * + * Returns 8 if the value is zero. Note that the GCC builtin is + * undefined if the value is zero. + * + * Note that the GCC builtin will upcast its argument to an `unsigned int` + * so this function subtracts off the number of prepended zeroes. + */ +static inline int clz8(uint8_t val) +{ + return val ? __builtin_clz(val) - 24 : 8; +} + +/** + * clz16 - count leading zeros in a 16-bit value. + * @val: The value to search + * + * Returns 16 if the value is zero. Note that the GCC builtin is + * undefined if the value is zero. + * + * Note that the GCC builtin will upcast its argument to an `unsigned int` + * so this function subtracts off the number of prepended zeroes. + */ +static inline int clz16(uint16_t val) +{ + return val ? __builtin_clz(val) - 16 : 16; +} + +/** * clz32 - count leading zeros in a 32-bit value. * @val: The value to search * @@ -154,6 +184,30 @@ static inline int clo64(uint64_t val) } /** + * ctz8 - count trailing zeros in a 8-bit value. + * @val: The value to search + * + * Returns 8 if the value is zero. Note that the GCC builtin is + * undefined if the value is zero. + */ +static inline int ctz8(uint8_t val) +{ + return val ? __builtin_ctz(val) : 8; +} + +/** + * ctz16 - count trailing zeros in a 16-bit value. + * @val: The value to search + * + * Returns 16 if the value is zero. Note that the GCC builtin is + * undefined if the value is zero. + */ +static inline int ctz16(uint16_t val) +{ + return val ? __builtin_ctz(val) : 16; +} + +/** * ctz32 - count trailing zeros in a 32-bit value. * @val: The value to search * |