swab.h

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#ifndef _ASM_X86_SWAB_H
#define _ASM_X86_SWAB_H

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

static inline __attribute_const__ __u32 __arch_swab32(__u32 val)
{
#ifdef __i386__
# ifdef CONFIG_X86_BSWAP
    asm("bswap %0" : "=r" (val) : "0" (val));
# else
    asm("xchgb %b0,%h0\n\t" /* swap lower bytes */
        "rorl $16,%0\n\t"   /* swap words       */
        "xchgb %b0,%h0" /* swap higher bytes    */
        : "=q" (val)
        : "0" (val));
# endif

#else /* __i386__ */
    asm("bswapl %0"
        : "=r" (val)
        : "0" (val));
#endif
    return val;
}
#define __arch_swab32 __arch_swab32

static inline __attribute_const__ __u64 __arch_swab64(__u64 val)
{
#ifdef __i386__
    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__ */
    asm("bswapq %0"
        : "=r" (val)
        : "0" (val));
    return val;
#endif
}
#define __arch_swab64 __arch_swab64

#endif /* _ASM_X86_SWAB_H */