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/******************************************************************************
* string.c
*
* These provide something for compiler-emitted string operations to link
* against.
*/
#include <xen/config.h>
#include <xen/lib.h>
#undef memcpy
void *memcpy(void *dest, const void *src, size_t n)
{
long d0, d1, d2;
asm volatile (
" rep ; movs"__OS" ; "
" mov %4,%3 ; "
" rep ; movsb "
: "=&c" (d0), "=&D" (d1), "=&S" (d2)
: "0" (n/BYTES_PER_LONG), "r" (n%BYTES_PER_LONG), "1" (dest), "2" (src)
: "memory" );
return dest;
}
#undef memset
void *memset(void *s, int c, size_t n)
{
long d0, d1;
asm volatile (
"rep stosb"
: "=&c" (d0), "=&D" (d1)
: "a" (c), "1" (s), "0" (n)
: "memory");
return s;
}
#undef memmove
void *memmove(void *dest, const void *src, size_t n)
{
long d0, d1, d2;
if ( dest < src )
return memcpy(dest, src, n);
asm volatile (
" std ; "
" rep movsb ; "
" cld "
: "=&c" (d0), "=&S" (d1), "=&D" (d2)
: "0" (n), "1" (n-1+(const char *)src), "2" (n-1+(char *)dest)
: "memory");
return dest;
}
/*
* Local variables:
* mode: C
* c-file-style: "BSD"
* c-basic-offset: 4
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/
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