byteorder.h

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#ifndef _I386_BYTEORDER_H
#define _I386_BYTEORDER_H
 
//#include "types.h"
#include "compiler.h"
 
#ifdef __GNUC__
 
/* For avoiding bswap on i386 */
//#ifdef __KERNEL__
//#include <linux/config.h>
//#endif
 
static __inline__ __attribute_const__ __u32 ___arch__swab32(__u32 x)
{
#ifdef CONFIG_X86_BSWAP
    __asm__("bswap %0" : "=r" (x) : "0" (x));
#else
    __asm__("xchgb %b0,%h0\n\t" /* swap lower bytes */
        "rorl $16,%0\n\t"   /* swap words       */
        "xchgb %b0,%h0"     /* swap higher bytes    */
        :"=q" (x)
        : "0" (x));
#endif
    return x;
}
 
static __inline__ __attribute_const__ __u64 ___arch__swab64(__u64 val)
{
    union {
        struct { __u32 a,b; } s;
        __u64 u;
    } v;
    v.u = val;
#ifdef CONFIG_X86_BSWAP
    asm("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
        : "=r" (v.s.a), "=r" (v.s.b)
        : "0" (v.s.a), "1" (v.s.b));
#else
   v.s.a = ___arch__swab32(v.s.a);
    v.s.b = ___arch__swab32(v.s.b);
    asm("xchgl %0,%1" : "=r" (v.s.a), "=r" (v.s.b) : "0" (v.s.a), "1" (v.s.b));
#endif
    return v.u;
}
 
/* Do not define swab16.  Gcc is smart enough to recognize "C" version and
   convert it into rotation or exhange.  */
 
#define __arch__swab64(x) ___arch__swab64(x)
#define __arch__swab32(x) ___arch__swab32(x)
 
#define __BYTEORDER_HAS_U64__
 
#endif /* __GNUC__ */
 
//#include "little_endian.h"
 
#endif /* _I386_BYTEORDER_H */