代码

#pragma GCC optimize("Ofast,-funroll-loops")
#pragma GCC target("mmx")
#include<immintrin.h>
#include<emmintrin.h>
void my_memset(char *a, char c, unsigned n){
	n--;
	while((n&7)!=7&&n>=0)a[n]=c,n--;
	if(n==-1)return ;
	__m64 fa=_mm_set1_pi8(c);
	__m64* _a=(__m64*)a;
	for(int i=0;i<n;i+=8,_a++)*_a=fa;
}

评测结果