string_64.h

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#ifndef _ASM_X86_STRING_64_H
#define _ASM_X86_STRING_64_H

#ifdef __KERNEL__

/* Written 2002 by Andi Kleen */

/* Only used for special circumstances. Stolen from i386/string.h */
static __always_inline void *__inline_memcpy(void *to, const void *from, size_t n)
{
    unsigned long d0, d1, d2;
    asm volatile("rep ; movsl\n\t"
             "testb $2,%b4\n\t"
             "je 1f\n\t"
             "movsw\n"
             "1:\ttestb $1,%b4\n\t"
             "je 2f\n\t"
             "movsb\n"
             "2:"
             : "=&c" (d0), "=&D" (d1), "=&S" (d2)
             : "0" (n / 4), "q" (n), "1" ((long)to), "2" ((long)from)
             : "memory");
    return to;
}

/* Even with __builtin_ the compiler may decide to use the out of line
   function. */

#define __HAVE_ARCH_MEMCPY 1
#ifndef CONFIG_KMEMCHECK
#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) || __GNUC__ > 4
extern void *memcpy(void *to, const void *from, size_t len);
#else
extern void *__memcpy(void *to, const void *from, size_t len);
#define memcpy(dst, src, len)                   \
({                              \
    size_t __len = (len);                   \
    void *__ret;                        \
    if (__builtin_constant_p(len) && __len >= 64)       \
        __ret = __memcpy((dst), (src), __len);      \
    else                            \
        __ret = __builtin_memcpy((dst), (src), __len);  \
    __ret;                          \
})
#endif
#else
/*
 * kmemcheck becomes very happy if we use the REP instructions unconditionally,
 * because it means that we know both memory operands in advance.
 */
#define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
#endif

#define __HAVE_ARCH_MEMSET
void *memset(void *s, int c, size_t n);

#define __HAVE_ARCH_MEMMOVE
void *memmove(void *dest, const void *src, size_t count);

int memcmp(const void *cs, const void *ct, size_t count);
size_t strlen(const char *s);
char *strcpy(char *dest, const char *src);
char *strcat(char *dest, const char *src);
int strcmp(const char *cs, const char *ct);

#endif /* __KERNEL__ */

#endif /* _ASM_X86_STRING_64_H */