diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/qemu/host-utils.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index 7d36ebfd5b..3ef97d503d 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -26,6 +26,7 @@ #define HOST_UTILS_H 1 #include "qemu/compiler.h" /* QEMU_GNUC_PREREQ */ +#include "qemu/bswap.h" #include <limits.h> #include <stdbool.h> @@ -391,6 +392,80 @@ static inline int ctpop64(uint64_t val) #endif } +/** + * revbit8 - reverse the bits in an 8-bit value. + * @x: The value to modify. + */ +static inline uint8_t revbit8(uint8_t x) +{ + /* Assign the correct nibble position. */ + x = ((x & 0xf0) >> 4) + | ((x & 0x0f) << 4); + /* Assign the correct bit position. */ + x = ((x & 0x88) >> 3) + | ((x & 0x44) >> 1) + | ((x & 0x22) << 1) + | ((x & 0x11) << 3); + return x; +} + +/** + * revbit16 - reverse the bits in a 16-bit value. + * @x: The value to modify. + */ +static inline uint16_t revbit16(uint16_t x) +{ + /* Assign the correct byte position. */ + x = bswap16(x); + /* Assign the correct nibble position. */ + x = ((x & 0xf0f0) >> 4) + | ((x & 0x0f0f) << 4); + /* Assign the correct bit position. */ + x = ((x & 0x8888) >> 3) + | ((x & 0x4444) >> 1) + | ((x & 0x2222) << 1) + | ((x & 0x1111) << 3); + return x; +} + +/** + * revbit32 - reverse the bits in a 32-bit value. + * @x: The value to modify. + */ +static inline uint32_t revbit32(uint32_t x) +{ + /* Assign the correct byte position. */ + x = bswap32(x); + /* Assign the correct nibble position. */ + x = ((x & 0xf0f0f0f0u) >> 4) + | ((x & 0x0f0f0f0fu) << 4); + /* Assign the correct bit position. */ + x = ((x & 0x88888888u) >> 3) + | ((x & 0x44444444u) >> 1) + | ((x & 0x22222222u) << 1) + | ((x & 0x11111111u) << 3); + return x; +} + +/** + * revbit64 - reverse the bits in a 64-bit value. + * @x: The value to modify. + */ +static inline uint64_t revbit64(uint64_t x) +{ + /* Assign the correct byte position. */ + x = bswap64(x); + /* Assign the correct nibble position. */ + x = ((x & 0xf0f0f0f0f0f0f0f0ull) >> 4) + | ((x & 0x0f0f0f0f0f0f0f0full) << 4); + /* Assign the correct bit position. */ + x = ((x & 0x8888888888888888ull) >> 3) + | ((x & 0x4444444444444444ull) >> 1) + | ((x & 0x2222222222222222ull) << 1) + | ((x & 0x1111111111111111ull) << 3); + return x; +} + /* Host type specific sizes of these routines. */ #if ULONG_MAX == UINT32_MAX @@ -399,12 +474,14 @@ static inline int ctpop64(uint64_t val) # define clol clo32 # define ctol cto32 # define ctpopl ctpop32 +# define revbitl revbit32 #elif ULONG_MAX == UINT64_MAX # define clzl clz64 # define ctzl ctz64 # define clol clo64 # define ctol cto64 # define ctpopl ctpop64 +# define revbitl revbit64 #else # error Unknown sizeof long #endif |