代码

void my_memset(char *__restrict__ a, char c, unsigned n)
{
    unsigned i = 0;
    /* 4 路展开 */
    for (; i + 3 < n; i += 4)
    {
        a[i]     = c;
        a[i + 1] = c;
        a[i + 2] = c;
        a[i + 3] = c;
    }
    /* 收尾 */
    for (; i < n; ++i)
    {
        a[i] = c;
    }
}

评测结果