Re: Setting A in C-instruction

Posted by eatmorepies on
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/Setting-A-in-C-instruction-tp4036936p4036959.html

Shoot, I had meant to write RAM instead of ROM in regards to where the a-register value is sent.

Instructions persist in ROM, program data is stored in RAM. inM gets a value from RAM based on the address that was supplied to the RAM in the previous instruction. Values are supplied to RAM given the CPU's outM and addressM values, and are written depending on the current value of writeM.

I understand what you mean concerning the different chips the A register value is outputted to; the CPU wouldn't be able to save and load data from the RAM if that value wasn't outputted to addressM, nor would jumps work if we did not supply the PC with an address to jump to. That is what I had in mind, but I should have been more explicit in my previous comment.

Thanks for your help.