include/asm-i386/byteorder.h

   1 #ifndef _I386_BYTEORDER_H
   2 #define _I386_BYTEORDER_H
   3
   4 #include <asm/types.h>
   5 #include <linux/compiler.h>
   6
   7 #ifdef __GNUC__
   8
   9 /* For avoiding bswap on i386 */
  10 #ifdef __KERNEL__
  11 #include <linux/config.h>
  12 #endif
  13
  14 static __inline__ __attribute_const__ __u32 ___arch__swab32(__u32 x)
  15 {
  16 #ifdef CONFIG_X86_BSWAP
  17         __asm__("bswap %0" : "=r" (x) : "0" (x));
  18 #else
  19         __asm__("xchgb %b0,%h0\n\t"     /* swap lower bytes     */
  20                 "rorl $16,%0\n\t"       /* swap words           */
  21                 "xchgb %b0,%h0"         /* swap higher bytes    */
  22                 :"=q" (x)
  23                 : "0" (x));
  24 #endif
  25         return x;
  26 }
  27
  28 static __inline__ __attribute_const__ __u64 ___arch__swab64(__u64 val)
  29 {
  30         union {
  31                 struct { __u32 a,b; } 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" : "=r" (v.s.a), "=r" (v.s.b) : "0" (v.s.a), "1" (v.s.b));
  43 #endif
  44         return v.u;
  45 }
  46
  47 /* Do not define swab16.  Gcc is smart enough to recognize "C" version and
  48    convert it into rotation or exhange.  */
  49
  50 #define __arch__swab64(x) ___arch__swab64(x)
  51 #define __arch__swab32(x) ___arch__swab32(x)
  52
  53 #define __BYTEORDER_HAS_U64__
  54
  55 #endif /* __GNUC__ */
  56
  57 #include <linux/byteorder/little_endian.h>
  58
  59 #endif /* _I386_BYTEORDER_H */