bswap.h

   1 #ifndef __BSWAP_H__
   2 #define __BSWAP_H__
   3
   4 #ifdef HAVE_BYTESWAP_H
   5 #include <byteswap.h>
   6 #else
   7
   8 #include <inttypes.h>
   9
  10 #ifdef ARCH_X86_64
  11 #  define LEGACY_REGS "=Q"
  12 #else
  13 #  define LEGACY_REGS "=q"
  14 #endif
  15
  16 #if defined(ARCH_X86) || defined(ARCH_X86_64)
  17 static inline uint16_t ByteSwap16(uint16_t x)
  18 {
  19   __asm("xchgb %b0,%h0" :
  20         LEGACY_REGS (x) :
  21         "0" (x));
  22     return x;
  23 }
  24 #define bswap_16(x) ByteSwap16(x)
  25
  26 static inline uint32_t ByteSwap32(uint32_t x)
  27 {
  28 #if __CPU__ > 386
  29  __asm("bswap   %0":
  30       "=r" (x)     :
  31 #else
  32  __asm("xchgb   %b0,%h0\n"
  33       " rorl    $16,%0\n"
  34       " xchgb   %b0,%h0":
  35       LEGACY_REGS (x)           :
  36 #endif
  37       "0" (x));
  38   return x;
  39 }
  40 #define bswap_32(x) ByteSwap32(x)
  41
  42 static inline uint64_t ByteSwap64(uint64_t x)
  43 {
  44 #ifdef ARCH_X86_64
  45   __asm("bswap  %0":
  46         "=r" (x)     :
  47         "0" (x));
  48   return x;
  49 #else
  50   register union { __extension__ uint64_t __ll;
  51           uint32_t __l[2]; } __x;
  52   asm("xchgl    %0,%1":
  53       "=r"(__x.__l[0]),"=r"(__x.__l[1]):
  54       "0"(bswap_32((unsigned long)x)),"1"(bswap_32((unsigned long)(x>>32))));
  55   return __x.__ll;
  56 #endif
  57 }
  58 #define bswap_64(x) ByteSwap64(x)
  59
  60 #elif defined(ARCH_SH4)
  61
  62 static inline uint16_t ByteSwap16(uint16_t x) {
  63         __asm__("swap.b %0,%0":"=r"(x):"0"(x));
  64         return x;
  65 }
  66
  67 static inline uint32_t ByteSwap32(uint32_t x) {
  68         __asm__(
  69         "swap.b %0,%0\n"
  70         "swap.w %0,%0\n"
  71         "swap.b %0,%0\n"
  72         :"=r"(x):"0"(x));
  73         return x;
  74 }
  75
  76 #define bswap_16(x) ByteSwap16(x)
  77 #define bswap_32(x) ByteSwap32(x)
  78
  79 static inline uint64_t ByteSwap64(uint64_t x)
  80 {
  81     union {
  82         uint64_t ll;
  83         struct {
  84            uint32_t l,h;
  85         } l;
  86     } r;
  87     r.l.l = bswap_32 (x);
  88     r.l.h = bswap_32 (x>>32);
  89     return r.ll;
  90 }
  91 #define bswap_64(x) ByteSwap64(x)
  92
  93 #else
  94
  95 #define bswap_16(x) (((x) & 0x00ff) << 8 | ((x) & 0xff00) >> 8)
  96
  97
  98 // code from bits/byteswap.h (C) 1997, 1998 Free Software Foundation, Inc.
  99 #define bswap_32(x) \
 100      ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) | \
 101       (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))
 102
 103 static inline uint64_t ByteSwap64(uint64_t x)
 104 {
 105     union {
 106         uint64_t ll;
 107         uint32_t l[2];
 108     } w, r;
 109     w.ll = x;
 110     r.l[0] = bswap_32 (w.l[1]);
 111     r.l[1] = bswap_32 (w.l[0]);
 112     return r.ll;
 113 }
 114 #define bswap_64(x) ByteSwap64(x)
 115
 116 #endif  /* !ARCH_X86 */
 117
 118 #endif  /* !HAVE_BYTESWAP_H */
 119
 120 // be2me ... BigEndian to MachineEndian
 121 // le2me ... LittleEndian to MachineEndian
 122
 123 #ifdef WORDS_BIGENDIAN
 124 #define be2me_16(x) (x)
 125 #define be2me_32(x) (x)
 126 #define be2me_64(x) (x)
 127 #define le2me_16(x) bswap_16(x)
 128 #define le2me_32(x) bswap_32(x)
 129 #define le2me_64(x) bswap_64(x)
 130 #else
 131 #define be2me_16(x) bswap_16(x)
 132 #define be2me_32(x) bswap_32(x)
 133 #define be2me_64(x) bswap_64(x)
 134 #define le2me_16(x) (x)
 135 #define le2me_32(x) (x)
 136 #define le2me_64(x) (x)
 137 #endif
 138
 139 #endif /* __BSWAP_H__ */