PDP8 and Z-machine engine

[Johnny Billquist]

David Griffith <dgriffi at cs.csubak.edu> wrote:

> On Sat, 2 Sep 2006, Gordon JC Pearce wrote:
> 
> 
>>Interesting.  Looking (very quickly) at the Z-machine spec, it seems
>>fairly simple.  This gives me a good excuse to start on my PDP-8
>>emulator again - at least that way if I need more core, I just need to
>>change a #define instead of starting a big long thread about
>>semiconductor memory ;-)
> 
> I don't mean to discourage you, but you might be in for more challenge
> than you bargained for.  I asked Brian Moriarty about the feasability of
> porting a modern Z-machine emulator to 6502 machines such as the Commodore
> 64 and Apple IIe.  He replied that past V3, the abilities of these
> machines were seriously taxed and that's why Infocom abandoned that class
> of machines for their later work.  The full discussion can be found in the
> Frotz documentation.  Based on this, I don't recommend using Frotz as a
> starting point.
> 
> Look instead at ZXZVM, a Z-machine emulator written in Z80 assembly for
> PCW machines.  It should be reasonably easy to port to CP/M and/or ZSDOS.
> I'd love to see that one for my P112.  Doing that may provide enough
> insight to port it to the PDP8.

Frotz???
Why on earth base it on Frotz? Frotz is written in C. You'll never get 
anything meaningful written in C to run on a PDP-8.
Something written in Z80 assembly is just about equally meaningless.

No, you'd just have to write it from scratch. Nothing strange about 
that, and doing something about V4 and V5 games isn't that difficult 
either. Given a little time I sure could whip one together, but for now 
I'll leave the exercise to someone else.
I've already written one Z-machine interpreter in MACRO-11. It deals 
with anything V1 to V8, except for obvious limitations (no sounds, no 
graphics, no mouse...)

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol