(SOLVED) 41CL - DOUBLE HEPAX ACCESS and MMU CONFIG

[Monte Dalrymple]

As is mentioned in the manual, Configuration F requires more work to use because in CFG F the YFNX image is in a different page than all of the other configurations. This means that if you try to load this configuration directly, when the function terminates the code won't be there any more and you'll get a MEMORY LOST.

To switch to CFG F and HP-IL you will need to do the following:

MMUDIS (disable MMU and force the machine to use YFNZ in page 7)
XEQ MMUCLR (clear all of the previous configuration)
"YFNX" (select YFNX)
XEQ PLUG3U (plug YFNX into Port 3 upper half)
XEQ MMUEN (enable the MMU with YFNX in the location consistent with CFG F)
XEQ RCLCFG F (load CFG F)

Now you can turn off the machine and plug in the HP-IL module.


When you want to switch back to another configuration:

Turn off the machine and remove the HP-IL module.
Turn the machine back on.

MMUDIS (disable MMU and force the machine to use YFNZ in page 7)
XEQ MMUCLR (clear all of the previous configuration)
"YFNX" (select YFNX)
XEQ PLUGH (plug YFNX into Page 7 where the HP-IL module resided)
XEQ MMUEN (enable the MMU with YFNX in Page 7)
XEQ RCLCFG 0 (load CFG 0 or whatever other configuration you prefer)


I will be adding this information to the Extreme Functions manual. I originally left it as an exercise for the reader, which was clearly a mistake.

If there was room in the code it would obviously be better to recognize where YFNX was located and automatically handle all of this stuff. But I'm pretty sure that there aren't enough bytes left to do this.