Well, I have the basics implemented now for QUAD support in REX, for M100. I made the dumbest mistake thought and it really cost me some time. I had loaded my VirtualT instance with the M100 ROM from the EU debug exercise..and of course that ROM doesn't work with REX. So, it cost me a whole pile of time before I realized what I had done and why debugging was so challenging.
Interestingly I think I know why REX doesn't work with that other ROM - the standard ROM issues DI almost right away, killing the timer till after setup. In the problematic EU version, interrupts are enabled on power up. At least that's my theory but I'm not going further with this, for now. Steve
