From eebe3fcd2a5728264faa5ae72bbc38d7bb704c8e Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Wed, 21 Mar 2018 17:53:40 +0100 Subject: [PATCH 1/1] utils: use constant byte-order conversion Simplifies portability and ensures that cpu_to_* can be used in const declarations. If the architecture has special instructions, the compiler should be able to detect the pattern and use them. Signed-off-by: Felix Fietkau --- utils.h | 59 +++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 33 insertions(+), 26 deletions(-) diff --git a/utils.h b/utils.h index e72d947..aa480e2 100644 --- a/utils.h +++ b/utils.h @@ -81,16 +81,10 @@ int clock_gettime(int type, struct timespec *tv); #elif defined(__APPLE__) #include #include -#define bswap_32(x) OSSwapInt32(x) -#define bswap_64(x) OSSwapInt64(x) #elif defined(__FreeBSD__) #include -#define bswap_32(x) bswap32(x) -#define bswap_64(x) bswap64(x) #else #include -#define bswap_32(x) swap32(x) -#define bswap_64(x) swap64(x) #endif #ifndef __BYTE_ORDER @@ -103,28 +97,41 @@ int clock_gettime(int type, struct timespec *tv); #define __LITTLE_ENDIAN LITTLE_ENDIAN #endif +#define __constant_swap16(x) ((uint16_t)( \ + (((uint16_t)(x) & (uint16_t)0x00ffU) << 8) | \ + (((uint16_t)(x) & (uint16_t)0xff00U) >> 8))) + +#define __constant_swap32(x) ((uint32_t)( \ + (((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) | \ + (((uint32_t)(x) & (uint32_t)0x0000ff00UL) << 8) | \ + (((uint32_t)(x) & (uint32_t)0x00ff0000UL) >> 8) | \ + (((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24))) + +#define __constant_swap64(x) ((uint64_t)( \ + (((uint64_t)(x) & (uint64_t)0x00000000000000ffULL) << 56) | \ + (((uint64_t)(x) & (uint64_t)0x000000000000ff00ULL) << 40) | \ + (((uint64_t)(x) & (uint64_t)0x0000000000ff0000ULL) << 24) | \ + (((uint64_t)(x) & (uint64_t)0x00000000ff000000ULL) << 8) | \ + (((uint64_t)(x) & (uint64_t)0x000000ff00000000ULL) >> 8) | \ + (((uint64_t)(x) & (uint64_t)0x0000ff0000000000ULL) >> 24) | \ + (((uint64_t)(x) & (uint64_t)0x00ff000000000000ULL) >> 40) | \ + (((uint64_t)(x) & (uint64_t)0xff00000000000000ULL) >> 56))) + + static inline uint16_t __u_bswap16(uint16_t val) { return ((val >> 8) & 0xffu) | ((val & 0xffu) << 8); } -#if _GNUC_MIN_VER(4, 2) -#define __u_bswap32(x) __builtin_bswap32(x) -#define __u_bswap64(x) __builtin_bswap64(x) -#else -#define __u_bswap32(x) bswap_32(x) -#define __u_bswap64(x) bswap_64(x) -#endif - #if __BYTE_ORDER == __LITTLE_ENDIAN -#define cpu_to_be64(x) __u_bswap64(x) -#define cpu_to_be32(x) __u_bswap32(x) -#define cpu_to_be16(x) __u_bswap16((uint16_t) (x)) +#define cpu_to_be64(x) __constant_swap64(x) +#define cpu_to_be32(x) __constant_swap32(x) +#define cpu_to_be16(x) __constant_swap16(x) -#define be64_to_cpu(x) __u_bswap64(x) -#define be32_to_cpu(x) __u_bswap32(x) -#define be16_to_cpu(x) __u_bswap16((uint16_t) (x)) +#define be64_to_cpu(x) __constant_swap64(x) +#define be32_to_cpu(x) __constant_swap32(x) +#define be16_to_cpu(x) __constant_swap16(x) #define cpu_to_le64(x) (x) #define cpu_to_le32(x) (x) @@ -136,13 +143,13 @@ static inline uint16_t __u_bswap16(uint16_t val) #else /* __BYTE_ORDER == __LITTLE_ENDIAN */ -#define cpu_to_le64(x) __u_bswap64(x) -#define cpu_to_le32(x) __u_bswap32(x) -#define cpu_to_le16(x) __u_bswap16((uint16_t) (x)) +#define cpu_to_le64(x) __constant_swap64(x) +#define cpu_to_le32(x) __constant_swap32(x) +#define cpu_to_le16(x) __constant_swap16(x) -#define le64_to_cpu(x) __u_bswap64(x) -#define le32_to_cpu(x) __u_bswap32(x) -#define le16_to_cpu(x) __u_bswap16((uint16_t) (x)) +#define le64_to_cpu(x) __constant_swap64(x) +#define le32_to_cpu(x) __constant_swap32(x) +#define le16_to_cpu(x) __constant_swap16(x) #define cpu_to_be64(x) (x) #define cpu_to_be32(x) (x) -- 2.11.0