**10100，此时((long)d | (long)s) & lmask = 0，即对齐的话不做if中的语句，直接从整字开始copy内存内容 否则，((long)d | (long)s) & lmask 非0，进入if语句：if(((long)d ^ (long)s) & lmask) || (count < lsize)) 中，记住lmask = 000……00011，所以(long)d ^ (...