bswap.h

   1 #ifndef __BSWAP_H__
   2 #define __BSWAP_H__
   3
   4 #ifdef HAVE_CONFIG_H
   5 #include "config.h"
   6 #endif
   7
   8 #ifdef HAVE_BYTESWAP_H
   9 #include <byteswap.h>
  10 #else
  11
  12 #include <inttypes.h>
  13
  14 #ifdef ARCH_X86
  15 inline static unsigned short ByteSwap16(unsigned short x)
  16 {
  17   __asm("xchgb %b0,%h0" :
  18         "=q" (x)        :
  19         "0" (x));
  20     return x;
  21 }
  22 #define bswap_16(x) ByteSwap16(x)
  23
  24 inline static unsigned int ByteSwap32(unsigned int x)
  25 {
  26 #if __CPU__ > 386
  27  __asm("bswap   %0":
  28       "=r" (x)     :
  29 #else
  30  __asm("xchgb   %b0,%h0\n"
  31       " rorl    $16,%0\n"
  32       " xchgb   %b0,%h0":
  33       "=q" (x)          :
  34 #endif
  35       "0" (x));
  36   return x;
  37 }
  38 #define bswap_32(x) ByteSwap32(x)
  39
  40 inline static unsigned long long int ByteSwap64(unsigned long long int x)
  41 {
  42   register union { __extension__ unsigned long long int __ll;
  43           unsigned long int __l[2]; } __x;
  44   asm("xchgl    %0,%1":
  45       "=r"(__x.__l[0]),"=r"(__x.__l[1]):
  46       "0"(bswap_32((unsigned long)x)),"1"(bswap_32((unsigned long)(x>>32))));
  47   return __x.__ll;
  48 }
  49 #define bswap_64(x) ByteSwap64(x)
  50
  51 #else
  52
  53 #define bswap_16(x) (((x) & 0x00ff) << 8 | ((x) & 0xff00) >> 8)
  54
  55
  56 // code from bits/byteswap.h (C) 1997, 1998 Free Software Foundation, Inc.
  57 #define bswap_32(x) \
  58      ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) | \
  59       (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))
  60
  61 #define bswap_64(x) \
  62      (__extension__                                             \
  63       ({ union { __extension__ unsigned long long int __ll;     \
  64                  unsigned long int __l[2]; } __w, __r;          \
  65          __w.__ll = (x);                                        \
  66          __r.__l[0] = bswap_32 (__w.__l[1]);                    \
  67          __r.__l[1] = bswap_32 (__w.__l[0]);                    \
  68          __r.__ll; }))
  69 #endif  /* !ARCH_X86 */
  70
  71 #endif  /* !HAVE_BYTESWAP_H */
  72
  73 // be2me ... BigEndian to MachineEndian
  74 // le2me ... LittleEndian to MachineEndian
  75
  76 #ifdef WORDS_BIGENDIAN
  77 #define be2me_16(x) (x)
  78 #define be2me_32(x) (x)
  79 #define be2me_64(x) (x)
  80 #define le2me_16(x) bswap_16(x)
  81 #define le2me_32(x) bswap_32(x)
  82 #define le2me_64(x) bswap_64(x)
  83 #else
  84 #define be2me_16(x) bswap_16(x)
  85 #define be2me_32(x) bswap_32(x)
  86 #define be2me_64(x) bswap_64(x)
  87 #define le2me_16(x) (x)
  88 #define le2me_32(x) (x)
  89 #define le2me_64(x) (x)
  90 #endif
  91
  92 #endif