arch/arm/include/asm/swab.h

   1 /*
   2  *  arch/arm/include/asm/byteorder.h
   3  *
   4  * ARM Endian-ness.  In little endian mode, the data bus is connected such
   5  * that byte accesses appear as:
   6  *  0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31
   7  * and word accesses (data or instruction) appear as:
   8  *  d0...d31
   9  *
  10  * When in big endian mode, byte accesses appear as:
  11  *  0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7
  12  * and word accesses (data or instruction) appear as:
  13  *  d0...d31
  14  */
  15 #ifndef __ASM_ARM_SWAB_H
  16 #define __ASM_ARM_SWAB_H
  17
  18 #include <uapi/asm/swab.h>
  19
  20 #if __LINUX_ARM_ARCH__ >= 6
  21
  22 static inline __attribute_const__ __u32 __arch_swahb32(__u32 x)
  23 {
  24         __asm__ ("rev16 %0, %1" : "=r" (x) : "r" (x));
  25         return x;
  26 }
  27 #define __arch_swahb32 __arch_swahb32
  28 #define __arch_swab16(x) ((__u16)__arch_swahb32(x))
  29
  30 static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
  31 {
  32         __asm__ ("rev %0, %1" : "=r" (x) : "r" (x));
  33         return x;
  34 }
  35 #define __arch_swab32 __arch_swab32
  36
  37 #endif
  38 #endif