在所有指令中，先是源操作数，然后才是目的操作数。

In any instruction, source comes first and destination follows.

youdao

这样做的目的在于防止在空闲或者等待状态中锁存进了不想要的指令。当前执行的操作不受影响。

This prevents unwanted commands from being registered during idle or wait states. Operations already in progress are not affected.

youdao

因此，开发一个界面友好，易于操作的工作指令下达系统进行自动化处理变得十分重要，这正是本系统开发的目的和意义。

So , develop a good and easiy operate system is important to schools . This is the purpose and significance of develop the system.

youdao