[Coco] OS-9 Pascal P-code Interpreters

[Theodore (Alex) Evans]

On 08/20/2015 01:49 PM, Joel Ewy wrote:
> Hey, does anybody know if the OS-9 Pascal P-code interpreters are
> compatible with other, UCSD-style P-code interpreters, such as the one
> for the Apple II, CP/M, or the original IBM PC?  For a possible future
> exhibit of classic computers at a local maker space, I would like to try
> running a P-code program on a variety of vintage platforms, and I'd very
> much like the CoCo to be one of them.

The term P-code has been used arbitrarily in both a abstract sense (an
virtual machine code) and a concrete sense (UCSD P-Code).  There are
at least four versions of UCSD P-code and I don't know if they are
backward compatible.  The OS-9 Pascal compiler is written in P-code.
Logically, they took one of the UCSD versions and customized it so
that it would produce OS-9 modules and wrote a P-Code to 6809
translator.  If that is what was done, it should be possible to strip
off the module information and have another UCSD P-code interpreter
run it.  Personally I would see if the compiler would work under
another P-Code interpreter.  That would be a pretty sufficient test.
If that works, your demo would probably work.