CPU design-The basic action of machine structure decision

Organized together by a variety of electronic devices, it forms something called a machine. Essentially, a CPU is a machine. The action of a machine is not as complex as a human being, so it can always be divided into its simplest action. This is the simplest action we might call a basic action. From the structure of Figure 3 1, we can see that the data and address signals can be transmitted through bus buses, the control signal is generally only controlled by the controller to other parts of the transmission, only a small number of signs signal, such as accumulator da for the 0 logo line ZF, accumulator da for negative sign line NF, etc. is transmitted through the leased line to the controller, which directly affects the control signal output of the controller. The output data from the CPU must pass through a specific register, and the data can only be transmitted to the outside world if it is out of the output register. Regardless of whether the machine is a single operation or a data transfer, any change is an action. If this action can no longer be divided into its composition of the action, then it is a basic action. After each basic action of the CPU is completed, we call it a basic state. For a machine, the basic state is not able to be divided.

Based on the actual structure of figure 3-1, we can sum up some of its basic actions:

1. pc+1;

2. Span style= "font-family: ' Courier New ', courier; font-size:15px; " >mar+1

3. irom send control;

4. da send A;

5. dram send B;

......

You can look for the other basic actions of this structure yourself in Figure 3 1. Does this structure have any actions that cannot be achieved? Of course. For example, "Write Da Values to Irom" is an action that cannot be completed for this structure.

In short, the CPU this machine from one basic state to another basic state, is a basic action. In order to find out the basic method of accomplishing a certain task, we study the basic action of a fixed machine structure in order to organize some functions that the machine structure can accomplish.

CPU design-The basic action of machine structure decision