I am attempting to build some code using BDS C for use on with our Model
100/102/200 memory upgrade (
http://bitchin100.com/remem_project.htm ).
BDS C was the one (free) C compiler that I could find that had basic
support for C syntax (it has pointers to structs, for example).
Anyway, I have a few CP/M based laptops, an NEC 8500, 8401a, and an
Amstrad NC200 (which can run "ZCN"). I'd like to use the NEC 8500 to
compile some short C programs to 8080 assem and then use them on the
Model 100.
Here's the thing: the 8500 defaults to a mode where ROM takes 32K of the
address space. It has several nice apps there but no programming
language. I believe the machine has 64K of RAM, but the software won't
let me switch to 64K all-ram mode unless I have an external drive
attached (either a floppy disk drive controller or a ramdisk cartridge).
I don't have either. In any event it's not real useful in all-ram mode
without some kind of external storage containing applications and
utilities.
So here's my question:
Can drivers for CP/M machines be loaded at run-time?
My idea is that I could make a simple driver that communicates to some
serial-based disk drive controller, or hopefully someone has already
done something similar. How do I structure such a driver, and would it
have to be part of CP/M or can I patch it in at run-time?
-- John.