thunter0512
Veteran Member
Thanks Dave.It looks like something is wrong somewhere with either the accumulator or the ALU logic (at a guess).
Everything seems OK with d01 up to the CMA instruction. CMA doesn't seem to complement the accumulator for some reason...
I haven't got any time to look into it further now - but I will later in the week. I am not sure why anything has changed on my machine though...
EDIT: I did find an old post of the simulator source and a picture of it running CHEKMO over at #45
EDIT: V0.5 is here: #61
Dave
The V0.5 simulation works well and CHEKMO II runs ... OK runs may give the wrong impression ... works is more appropriate.
Both Logisim and the LD12 simulation are very impressive and I now feel reassured that a PDP-8/s re-implementation and simulation is within reach.
I will continue reading the book "The Art of Digital Design" with the knowledge that I now have the tools and a template to attempt a PDP-8/s.
Thanks to all who responded.