Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 3b88da4a authored by Joshua Clayton's avatar Joshua Clayton Committed by Greg Kroah-Hartman
Browse files

lib: add bitrev8x4() 



Add a function to reverse bytes within a 32 bit word.
Operate on a u32 rather than individual bytes.

Signed-off-by: default avatarJoshua Clayton <stillcompiling@gmail.com>
Signed-off-by: default avatarAlan Tull <atull@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 60acfa59

include/linux/bitrev.h

+19 −0
Original line number Diff line number Diff line
@@ -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;	\