arch/arm/include/asm/swab.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  arch/arm/include/asm/byteorder.h
   4  *
   5  * ARM Endian-ness.  In little endian mode, the data bus is connected such
   6  * that byte accesses appear as:
   7  *  0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31
   8  * and word accesses (data or instruction) appear as:
   9  *  d0...d31
  10  *
  11  * When in big endian mode, byte accesses appear as:
  12  *  0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7
  13  * and word accesses (data or instruction) appear as:
  14  *  d0...d31
  15  */
  16 #ifndef __ASM_ARM_SWAB_H
  17 #define __ASM_ARM_SWAB_H
  18
  19 #include <uapi/asm/swab.h>
  20
  21 #if __LINUX_ARM_ARCH__ >= 6
  22
  23 static inline __attribute_const__ __u32 __arch_swahb32(__u32 x)
  24 {
  25         __asm__ ("rev16 %0, %1" : "=r" (x) : "r" (x));
  26         return x;
  27 }
  28 #define __arch_swahb32 __arch_swahb32
  29 #define __arch_swab16(x) ((__u16)__arch_swahb32(x))
  30
  31 static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
  32 {
  33         __asm__ ("rev %0, %1" : "=r" (x) : "r" (x));
  34         return x;
  35 }
  36 #define __arch_swab32 __arch_swab32
  37
  38 #endif
  39 #endif