30 lines
582 B
C
30 lines
582 B
C
/*
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* memcpy.c
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*/
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#include <string.h>
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#include <stdint.h>
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void *memcpy(void *dst, const void *src, size_t n)
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{
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const char *p = src;
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char *q = dst;
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#if defined(__i386__)
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size_t nl = n >> 2;
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asm volatile("cld ; rep ; movsl ; movl %3,%0 ; rep ; movsb"
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: "+c" (nl), "+S" (p), "+D" (q)
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: "r" (n & 3));
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#elif defined(__x86_64__)
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size_t nq = n >> 3;
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asm volatile("cld ; rep ; movsq ; movl %3,%%ecx ; rep ; movsb"
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: "+c" (nq), "+S" (p), "+D" (q)
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: "r" ((uint32_t)(n & 7)));
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#else
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while ( n-- ) {
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*q++ = *p++;
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}
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#endif
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return dst;
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}
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