30 lines
560 B
C
30 lines
560 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":"+c" (nl),
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"+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":"+c"
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(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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