arch/x86/include/asm/swab.h

   1 #ifndef _ASM_X86_SWAB_H
   2 #define _ASM_X86_SWAB_H
   3
   4 #include <linux/types.h>
   5 #include <linux/compiler.h>
   6
   7 static inline __attribute_const__ __u32 __arch_swab32(__u32 val)
   8 {
   9 #ifdef __i386__
  10 # ifdef CONFIG_X86_BSWAP
  11         asm("bswap %0" : "=r" (val) : "0" (val));
  12 # else
  13         asm("xchgb %b0,%h0\n\t" /* swap lower bytes     */
  14             "rorl $16,%0\n\t"   /* swap words           */
  15             "xchgb %b0,%h0"     /* swap higher bytes    */
  16             : "=q" (val)
  17             : "0" (val));
  18 # endif
  19
  20 #else /* __i386__ */
  21         asm("bswapl %0"
  22             : "=r" (val)
  23             : "0" (val));
  24 #endif
  25         return val;
  26 }
  27 #define __arch_swab32 __arch_swab32
  28
  29 static inline __attribute_const__ __u64 __arch_swab64(__u64 val)
  30 {
  31 #ifdef __i386__
  32         union {
  33                 struct {
  34                         __u32 a;
  35                         __u32 b;
  36                 } s;
  37                 __u64 u;
  38         } v;
  39         v.u = val;
  40 # ifdef CONFIG_X86_BSWAP
  41         asm("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
  42             : "=r" (v.s.a), "=r" (v.s.b)
  43             : "0" (v.s.a), "1" (v.s.b));
  44 # else
  45         v.s.a = __arch_swab32(v.s.a);
  46         v.s.b = __arch_swab32(v.s.b);
  47         asm("xchgl %0,%1"
  48             : "=r" (v.s.a), "=r" (v.s.b)
  49             : "0" (v.s.a), "1" (v.s.b));
  50 # endif
  51         return v.u;
  52 #else /* __i386__ */
  53         asm("bswapq %0"
  54             : "=r" (val)
  55             : "0" (val));
  56         return val;
  57 #endif
  58 }
  59 #define __arch_swab64 __arch_swab64
  60
  61 #endif /* _ASM_X86_SWAB_H */