LXR linux/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
  23static 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
  31static 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
  40