util/vgabios/include/swab.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #ifndef _SWAB_H
   4 #define _SWAB_H
   5
   6 /*
   7  * linux/byteorder/swab.h
   8  * Byte-swapping, independently from CPU endianness
   9  *      swabXX[ps]?(foo)
  10  *
  11  * Francois-Rene Rideau <fare@tunes.org> 19971205
  12  *    separated swab functions from cpu_to_XX,
  13  *    to clean up support for bizarre-endian architectures.
  14  *
  15  * See asm-i386/byteorder.h and such for examples of how to provide
  16  * architecture-dependent optimized versions
  17  *
  18  */
  19
  20 /* casts are necessary for constants, because we never know how for sure
  21  * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
  22  */
  23 #define swab16(x) \
  24         ((unsigned short)( \
  25                 (((unsigned short)(x) & (unsigned short)0x00ffU) << 8) | \
  26                 (((unsigned short)(x) & (unsigned short)0xff00U) >> 8) ))
  27
  28 #define swab32(x) \
  29         ((unsigned int)( \
  30                 (((unsigned int)(x) & (unsigned int)0x000000ffUL) << 24) | \
  31                 (((unsigned int)(x) & (unsigned int)0x0000ff00UL) <<  8) | \
  32                 (((unsigned int)(x) & (unsigned int)0x00ff0000UL) >>  8) | \
  33                 (((unsigned int)(x) & (unsigned int)0xff000000UL) >> 24) ))
  34
  35 #define swab64(x) \
  36         ((uint64_t)( \
  37                 (((uint64_t)(x) & (uint64_t)0x00000000000000ffULL) << 56) | \
  38                 (((uint64_t)(x) & (uint64_t)0x000000000000ff00ULL) << 40) | \
  39                 (((uint64_t)(x) & (uint64_t)0x0000000000ff0000ULL) << 24) | \
  40                 (((uint64_t)(x) & (uint64_t)0x00000000ff000000ULL) <<  8) | \
  41                 (((uint64_t)(x) & (uint64_t)0x000000ff00000000ULL) >>  8) | \
  42                 (((uint64_t)(x) & (uint64_t)0x0000ff0000000000ULL) >> 24) | \
  43                 (((uint64_t)(x) & (uint64_t)0x00ff000000000000ULL) >> 40) | \
  44                 (((uint64_t)(x) & (uint64_t)0xff00000000000000ULL) >> 56) ))
  45
  46 #endif /* _SWAB_H */