Implementation

An architecture can have more than one implementation, depending on other factors (technology, speed, price, power consumption etc.). We are going to look at a cheap, simple implementation.

For each instruction in turn, the implementation must:

• Fetch the next instruction
• Decode the instruction
• Obey the instruction

We need extra registers, invisible to the user, e.g. to hold the current instruction while it is being decoded, and to communicate with the memory. See figure 2.

  

Figure 2: MU0 + invisible registers