include/asm-x86/byteorder.h

   1 #ifndef _ASM_X86_BYTEORDER_H
   2 #define _ASM_X86_BYTEORDER_H
   3
   4 #include <asm/types.h>
   5 #include <linux/compiler.h>
   6
   7 #ifdef __GNUC__
   8
   9 #ifdef __i386__
  10
  11 static inline __attribute_const__ __u32 ___arch__swab32(__u32 x)
  12 {
  13 #ifdef CONFIG_X86_BSWAP
  14         asm("bswap %0" : "=r" (x) : "0" (x));
  15 #else
  16         asm("xchgb %b0,%h0\n\t" /* swap lower bytes     */
  17             "rorl $16,%0\n\t"   /* swap words           */
  18             "xchgb %b0,%h0"     /* swap higher bytes    */
  19             : "=q" (x)
  20             : "0" (x));
  21 #endif
  22         return x;
  23 }
  24
  25 static inline __attribute_const__ __u64 ___arch__swab64(__u64 val)
  26 {
  27         union {
  28                 struct {
  29                         __u32 a;
  30                         __u32 b;
  31                 } s;
  32                 __u64 u;
  33         } v;
  34         v.u = val;
  35 #ifdef CONFIG_X86_BSWAP
  36         asm("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
  37             : "=r" (v.s.a), "=r" (v.s.b)
  38             : "0" (v.s.a), "1" (v.s.b));
  39 #else
  40         v.s.a = ___arch__swab32(v.s.a);
  41         v.s.b = ___arch__swab32(v.s.b);
  42         asm("xchgl %0,%1"
  43             : "=r" (v.s.a), "=r" (v.s.b)
  44             : "0" (v.s.a), "1" (v.s.b));
  45 #endif
  46         return v.u;
  47 }
  48
  49 #else /* __i386__ */
  50
  51 static inline __attribute_const__ __u64 ___arch__swab64(__u64 x)
  52 {
  53         asm("bswapq %0"
  54             : "=r" (x)
  55             : "0" (x));
  56         return x;
  57 }
  58
  59 static inline __attribute_const__ __u32 ___arch__swab32(__u32 x)
  60 {
  61         asm("bswapl %0"
  62             : "=r" (x)
  63             : "0" (x));
  64         return x;
  65 }
  66
  67 #endif
  68
  69 /* Do not define swab16.  Gcc is smart enough to recognize "C" version and
  70    convert it into rotation or exhange.  */
  71
  72 #define __arch__swab64(x) ___arch__swab64(x)
  73 #define __arch__swab32(x) ___arch__swab32(x)
  74
  75 #define __BYTEORDER_HAS_U64__
  76
  77 #endif /* __GNUC__ */
  78
  79 #include <linux/byteorder/little_endian.h>
  80
  81 #endif /* _ASM_X86_BYTEORDER_H */