Emulation of an Alto(was: Alto II (was Re: PDP-8 prices))

From: Hans Franke <Hans.Franke_at_mch20.sbs.de>
Date: Tue Jan 26 10:31:22 1999

> > The main reason is that as far as emulation goes, microcode is a totally
> > different animal than machine code. Things happen in parallel; although the
> > parts of the CPU are doing simple things (like simple arithmetic) they are
> > working together. You would have to duplicate them precisely and make a
> > single processor act as if it could do things in parallel. As Tony pointed
> > out, that may even involve accounting for certain individual logic gates.
> > The gate-level emulation by itself would be doable; the parallel-processing
> > emulation would be doable; both together would be much less doable.

> I was all set to write one until you told me it would be too hard, so I
> dropped the project :)

> Seems like these obstacles could be over come with some clever state
> machine programming.

As far as I can tell from my (very small) knowledge of the Alto in
special and my (a bit wider) knowledge of microprogramm controls I
think that an Alto emulation will be a _lot_ easyer than a C64 for
example. I don't think there are combinations that are based on specific
_minimum_ timings that can't be reached by modern processors (please,
Tony - or who ever - correct me here). Even with older processors it
should be possible, if, at least, the average execution timing is
the same. Don't forget, since it is only an emulation, the actual
hardware is again async to our emulation, and mybe even driven by
independant processors.

Gruss
H.

--
Ich denke, also bin ich, also gut
HRK
Received on Tue Jan 26 1999 - 10:31:22 GMT

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