linux/arch/x86/include/asm/byteorder.h

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#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 */