#include <string.h>

void* memcpy(void* _dest, const void* _src, size_t _n)
{
    int 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)_dest), "2"((long)_src)
        : "memory");
    return (_dest);
}