root/include/asm-x86/byteorder.h

INCLUDED FROM

DEFINITIONS

1. ___arch__swab32
2. ___arch__swab64
3. ___arch__swab64
4. ___arch__swab32

#ifndef ASM_X86__BYTEORDER_H
#define ASM_X86__BYTEORDER_H

#include <asm/types.h>
#include <linux/compiler.h>

#ifdef __GNUC__

#ifdef __i386__

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;
                        __u32 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;
}

#else /* __i386__ */

static inline __attribute_const__ __u64 ___arch__swab64(__u64 x)
{
        asm("bswapq %0"
            : "=r" (x)
            : "0" (x));
        return x;
}

static inline __attribute_const__ __u32 ___arch__swab32(__u32 x)
{
        asm("bswapl %0"
            : "=r" (x)
            : "0" (x));
        return x;
}

#endif

/* 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 <linux/byteorder/little_endian.h>

#endif /* ASM_X86__BYTEORDER_H */