On Fri, Jun 2, 2017 at 3:30 PM, Joshua Clayton <stillcompiling@xxxxxxxxx> wrote:
> Add a function to reverse bytes within a 32 bit word.
> Operate on a u32 rather than individual bytes.
>
> Signed-off-by: Joshua Clayton <stillcompiling@xxxxxxxxx>
Signed-off-by: Alan Tull <atull@xxxxxxxxxx>
> ---
> include/linux/bitrev.h | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
> index fb790b8449c1..b97be27e5a85 100644
> --- a/include/linux/bitrev.h
> +++ b/include/linux/bitrev.h
> @@ -29,6 +29,8 @@ static inline u32 __bitrev32(u32 x)
>
> #endif /* CONFIG_HAVE_ARCH_BITREVERSE */
>
> +#define __bitrev8x4(x) (__bitrev32(swab32(x)))
> +
> #define __constant_bitrev32(x) \
> ({ \
> u32 __x = x; \
> @@ -50,6 +52,15 @@ static inline u32 __bitrev32(u32 x)
> __x; \
> })
>
> +#define __constant_bitrev8x4(x) \
> +({ \
> + u32 __x = x; \
> + __x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4); \
> + __x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2); \
> + __x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1); \
> + __x; \
> +})
> +
> #define __constant_bitrev8(x) \
> ({ \
> u8 __x = x; \
> @@ -75,6 +86,14 @@ static inline u32 __bitrev32(u32 x)
> __bitrev16(__x); \
> })
>
> +#define bitrev8x4(x) \
> +({ \
> + u32 __x = x; \
> + __builtin_constant_p(__x) ? \
> + __constant_bitrev8x4(__x) : \
> + __bitrev8x4(__x); \
> + })
> +
> #define bitrev8(x) \
> ({ \
> u8 __x = x; \
> --
> 2.11.0
>
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
