| Message ID | 1467125451-16700-7-git-send-email-peter.maydell@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 28 June 2016 at 15:50, Peter Maydell <peter.maydell@linaro.org> wrote: > 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> > --- > include/qemu/bswap.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 58 insertions(+) > > diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h > index a17d9aa..be3233a 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. > + * > + * uint16_t le16_to_cpus(uint16_t *v); > + * uint32_t le32_to_cpus(uint32_t *v); > + * uint64_t le64_to_cpus(uint64_t *v); > + * uint16_t be16_to_cpus(uint16_t *v); > + * uint32_t be32_to_cpus(uint32_t *v); > + * uint64_t be64_to_cpus(uint64_t *v); Doh. All these prototypes, and the ones in the block below, should be 'void' return type rather than the integer type. > + * > + * Do an in-place conversion of the value pointed to by @v from the > + * specified format to the native endianness of the host CPU. > + * > + * uint16_t cpu_to_le16s(uint16_t *v); > + * uint32_t cpu_to_le32s(uint32_t *v); > + * uint64_t cpu_to_le64s(uint64_t *v); > + * uint16_t cpu_to_be16s(uint16_t *v); > + * uint32_t cpu_to_be32s(uint32_t *v); > + * uint64_t 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)\ > {\ > -- > 1.9.1 > > thanks -- PMM
On 06/28/2016 08:50 AM, Peter Maydell wrote: > 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> > --- > include/qemu/bswap.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 58 insertions(+) > With your followup patch for returning void on the in-place functions, Reviewed-by: Eric Blake <eblake@redhat.com>
diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h index a17d9aa..be3233a 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. + * + * uint16_t le16_to_cpus(uint16_t *v); + * uint32_t le32_to_cpus(uint32_t *v); + * uint64_t le64_to_cpus(uint64_t *v); + * uint16_t be16_to_cpus(uint16_t *v); + * uint32_t be32_to_cpus(uint32_t *v); + * uint64_t 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. + * + * uint16_t cpu_to_le16s(uint16_t *v); + * uint32_t cpu_to_le32s(uint32_t *v); + * uint64_t cpu_to_le64s(uint64_t *v); + * uint16_t cpu_to_be16s(uint16_t *v); + * uint32_t cpu_to_be32s(uint32_t *v); + * uint64_t 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)\ {\
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> --- include/qemu/bswap.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+)