Re: CPU implementation

Posted by ivant on
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/CPU-implementation-tp4034383p4034387.html

It's a bit hard to follow what you wrote. Why would you pass the op code to a not gate?

The CPU has two main modes: operate on A instruction or on C instruction. How can you distinguish this? This is part of the control subsystem of the CPU. Most of it is already shown on Figure 5.9, but there are some details missing. You can start by implementing them.

For example, there's control signal going to register A, which tells it if it should remember or ignore its input. What are the conditions for this?

Hint: you can leave the PC controls for last. They are important to implement the jump behavior, but are a bit "hairy" but also quite isolated. I found it easier to think of them last.