LXR coreboot/src/include/swab.h

   1#ifndef _SWAB_H
   2#define _SWAB_H
   3
   4/*
   5 * linux/byteorder/swab.h
   6 * Byte-swapping, independently from CPU endianness
   7 *      swabXX[ps]?(foo)
   8 *
   9 * Francois-Rene Rideau <fare@tunes.org> 19971205
  10 *    separated swab functions from cpu_to_XX,
  11 *    to clean up support for bizarre-endian architectures.
  12 *
  13 * See asm-i386/byteorder.h and suches for examples of how to provide
  14 * architecture-dependent optimized versions
  15 *
  16 */
  17
  18/* casts are necessary for constants, because we never know how for sure
  19 * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
  20 */
  21#define swab16(x) \
  22        ((unsigned short)( \
  23                (((unsigned short)(x) & (unsigned short)0x00ffU) << 8) | \
  24                (((unsigned short)(x) & (unsigned short)0xff00U) >> 8) ))
  25
  26#define swab32(x) \
  27        ((unsigned int)( \
  28                (((unsigned int)(x) & (unsigned int)0x000000ffUL) << 24) | \
  29                (((unsigned int)(x) & (unsigned int)0x0000ff00UL) <<  8) | \
  30                (((unsigned int)(x) & (unsigned int)0x00ff0000UL) >>  8) | \
  31                (((unsigned int)(x) & (unsigned int)0xff000000UL) >> 24) ))
  32
  33#endif /* _SWAB_H */
  34