先入先出队列，这是一种传统的按序执行方法，先进入的指令先完成并引退，跟着才执行第二条指令。是一种先进先出的数据缓存器，他与普通存储器的区别是没有外部读写地址线，这样使用起来非常简单，但缺点就是只能顺序写入数据，顺序的读出数据，其数据地址由内部读写指针自动加1完成，不能像普通存储器那样可以由地址线决定读取或写入某个指定的地址-First-in, first-out queue, which is a traditional sequential execution method, first enter the command to complete and retire, followed by the second instruction before it is implemented. Is a FIFO data buffer, and he is the difference between ordinary no external memory write address lines, so it is very simple, but the disadvantage is that the order can only write data, read data sequentially, the data address by the internal write pointer is automatically incremented to complete, not like ordinary memory address lines that can be read from or written to a decision to the address specified