Uploaded December 2019 | Updated September 2026, 1 week ago
This video is mostly explanation and updating the control EEPROMs, there is no need to add to the circuit to add this functionality. I had some comments that not everyone knows what a stack is, so I spend a little time explaining that before going into the implementation details.
Having the stack operations makes it vastly easier to program this thing, it feels a lot more like a "real processor" to me now. The test code is fairly simple but it does prove out the functionality. I also add the instruction "jmp di", I had been meaning to add this and it was convenient to do it now.
In the RAM video I briefly experienced what I thought was an address timing issue and worked around it in the test code. I was wrong about the source of that problem but it was a trivial fix so I didn't go into that in this video. The next video will be a tidy up and discussion video, I'll explain the problem then.
This video is mostly explanation and updating the control EEPROMs, there is no need to add to the circuit to add this functionality. I had some comments that not everyone knows what a stack is, so I spend a little time explaining that before going into the implementation details.
Having the stack operations makes it vastly easier to program this thing, it feels a lot more like a "real processor" to me now. The test code is fairly simple but it does prove out the functionality. I also add the instruction "jmp di", I had been meaning to add this and it was convenient to do it now.
In the RAM video I briefly experienced what I thought was an address timing issue and worked around it in the test code. I was wrong about the source of that problem but it was a trivial fix so I didn't go into that in this video. The next video will be a tidy up and discussion video, I'll explain the problem then.
