diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2016-07-07 17:21:00 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2016-07-12 15:08:53 +0100 |
| commit | 7d820b766a2049f33ca7e078aa51018f2335f8c5 (patch) | |
| tree | b8da825d2b3152a489a9f5831856f2f8d6b9671a | |
| parent | cbe967f41d60e387368ef597a90d544e7d368ddd (diff) | |
| download | qemu-7d820b766a2049f33ca7e078aa51018f2335f8c5.zip qemu-7d820b766a2049f33ca7e078aa51018f2335f8c5.tar.gz qemu-7d820b766a2049f33ca7e078aa51018f2335f8c5.tar.bz2 | |
bswap.h: Document cpu_to_* and *_to_cpu conversion functions
Add a documentation comment describing the functions for
converting between the cpu and little or bigendian formats.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1467908460-27048-6-git-send-email-peter.maydell@linaro.org
| -rw-r--r-- | include/qemu/bswap.h | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h index a17d9aa..09c78fd 100644 --- a/include/qemu/bswap.h +++ b/include/qemu/bswap.h @@ -80,6 +80,64 @@ static inline void bswap64s(uint64_t *s) #define be_bswaps(p, size) do { *p = glue(bswap, size)(*p); } while(0) #endif +/** + * Endianness conversion functions between host cpu and specified endianness. + * (We list the complete set of prototypes produced by the macros below + * to assist people who search the headers to find their definitions.) + * + * uint16_t le16_to_cpu(uint16_t v); + * uint32_t le32_to_cpu(uint32_t v); + * uint64_t le64_to_cpu(uint64_t v); + * uint16_t be16_to_cpu(uint16_t v); + * uint32_t be32_to_cpu(uint32_t v); + * uint64_t be64_to_cpu(uint64_t v); + * + * Convert the value @v from the specified format to the native + * endianness of the host CPU by byteswapping if necessary, and + * return the converted value. + * + * uint16_t cpu_to_le16(uint16_t v); + * uint32_t cpu_to_le32(uint32_t v); + * uint64_t cpu_to_le64(uint64_t v); + * uint16_t cpu_to_be16(uint16_t v); + * uint32_t cpu_to_be32(uint32_t v); + * uint64_t cpu_to_be64(uint64_t v); + * + * Convert the value @v from the native endianness of the host CPU to + * the specified format by byteswapping if necessary, and return + * the converted value. + * + * void le16_to_cpus(uint16_t *v); + * void le32_to_cpus(uint32_t *v); + * void le64_to_cpus(uint64_t *v); + * void be16_to_cpus(uint16_t *v); + * void be32_to_cpus(uint32_t *v); + * void be64_to_cpus(uint64_t *v); + * + * Do an in-place conversion of the value pointed to by @v from the + * specified format to the native endianness of the host CPU. + * + * void cpu_to_le16s(uint16_t *v); + * void cpu_to_le32s(uint32_t *v); + * void cpu_to_le64s(uint64_t *v); + * void cpu_to_be16s(uint16_t *v); + * void cpu_to_be32s(uint32_t *v); + * void cpu_to_be64s(uint64_t *v); + * + * Do an in-place conversion of the value pointed to by @v from the + * native endianness of the host CPU to the specified format. + * + * Both X_to_cpu() and cpu_to_X() perform the same operation; you + * should use whichever one is better documenting of the function your + * code is performing. + * + * Do not use these functions for conversion of values which are in guest + * memory, since the data may not be sufficiently aligned for the host CPU's + * load and store instructions. Instead you should use the ld*_p() and + * st*_p() functions, which perform loads and stores of data of any + * required size and endianness and handle possible misalignment. + */ + #define CPU_CONVERT(endian, size, type)\ static inline type endian ## size ## _to_cpu(type v)\ {\ |