linux/arch/arm/include/asm/swab.h
Linus Torvalds dca88ad691 Merge branch 'for-next' of git://git.infradead.org/users/dhowells/linux-headers
* 'for-next' of git://git.infradead.org/users/dhowells/linux-headers:
  UAPI: Split trivial #if defined(__KERNEL__) && X conditionals
  UAPI: Don't have a #elif clause in a __KERNEL__ guard in linux/soundcard.h
  UAPI: Fix AHZ multiple inclusion when __KERNEL__ is removed
  UAPI: Make linux/patchkey.h easier to parse
  UAPI: Fix nested __KERNEL__ guards in video/edid.h
  UAPI: Alter the S390 asm include guards to be recognisable by the UAPI splitter
  UAPI: Guard linux/cuda.h
  UAPI: Guard linux/pmu.h
  UAPI: Guard linux/isdn_divertif.h
  UAPI: Guard linux/sound.h
  UAPI: Rearrange definition of HZ in asm-generic/param.h
  UAPI: Make FRV use asm-generic/param.h
  UAPI: Make M32R use asm-generic/param.h
  UAPI: Make MN10300 use asm-generic/param.h
  UAPI: elf_read_implies_exec() is a kernel-only feature - so hide from userspace
  UAPI: Don't include linux/compat.h in sparc's asm/siginfo.h
  UAPI: Fix arch/mips/include/asm/Kbuild to have separate header-y lines
2012-01-14 18:03:30 -08:00

74 lines
1.8 KiB
C

/*
* arch/arm/include/asm/byteorder.h
*
* ARM Endian-ness. In little endian mode, the data bus is connected such
* that byte accesses appear as:
* 0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31
* and word accesses (data or instruction) appear as:
* d0...d31
*
* When in big endian mode, byte accesses appear as:
* 0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7
* and word accesses (data or instruction) appear as:
* d0...d31
*/
#ifndef __ASM_ARM_SWAB_H
#define __ASM_ARM_SWAB_H
#include <linux/compiler.h>
#include <linux/types.h>
#if !defined(__STRICT_ANSI__) || defined(__KERNEL__)
# define __SWAB_64_THRU_32__
#endif
#if defined(__KERNEL__)
#if __LINUX_ARM_ARCH__ >= 6
static inline __attribute_const__ __u32 __arch_swahb32(__u32 x)
{
__asm__ ("rev16 %0, %1" : "=r" (x) : "r" (x));
return x;
}
#define __arch_swahb32 __arch_swahb32
#define __arch_swab16(x) ((__u16)__arch_swahb32(x))
static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
{
__asm__ ("rev %0, %1" : "=r" (x) : "r" (x));
return x;
}
#define __arch_swab32 __arch_swab32
#endif
#endif
#if !defined(__KERNEL__) || __LINUX_ARM_ARCH__ < 6
static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
{
__u32 t;
#ifndef __thumb__
if (!__builtin_constant_p(x)) {
/*
* The compiler needs a bit of a hint here to always do the
* right thing and not screw it up to different degrees
* depending on the gcc version.
*/
asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x));
} else
#endif
t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */
x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */
t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */
x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */
return x;
}
#define __arch_swab32 __arch_swab32
#endif
#endif