Ang: RE: RE: Re: CP/M programming for the C128?

From: Mikael Holm (
Date: 2003-01-28 10:40:31

Hej Ruud,

Okay, now I see what you mean... 
And what I want to is to do just as CP/M is doing, use the original 
8502-routines to access the command channel. This is not supported by any 
CP/M service calls, with the exception of the USER function that can 
execute 8502 code... But as I wrote in another message, I have no idea 
about how to use this USER-service call.

About the Z80-boot ROM, is there a commented disassembly of it available 
anywhere on the net? Or any disassembly of it, commented or not...


Hallo Mikael, 
> But for me it's not an option, because I know even less about 
> sending pulses over the serial cable to a drive than I know 
> about CP/M... :-) 
This knowledge is not needed. What I meant was that the drive cannot know 
with what it is exchanging data. You also can reason the other way around: 
a normal C64 and C128 don't notice that 64HDD isn't a real 1541. 
Unfortunately a speedloader will as 64HDD doesn't execute 6502-ML ie. it 
is a simulator, not an emulator. But the C128 CP/M uses the original 8502- 
routines to address drives ie. no reprogramming of the drive. So IMHO CP/M 
won't see at all that the drive it is talking to a fake drive.
Another remark: a good source is the C128's own Z80-bootROM. 
   / __|__ 
  / /  |_/     Groetjes, Ruud 
  \ \__|_\ 

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