infocom on other systems

[Ethan Dicks]

On Mon, Sep 01, 2008 at 11:45:00PM -0700, Eric Smith wrote:
> Ethan Dicks wrote:
> >Fundamentally, I think one would have to scale up all the 16-bit Z-pointers
> >to 24-bits internally to a theoretical PDP-8 Z-machine, and there's a lot
> >of 16-bit math going on under the hood.
> 
> That sounds like the really hard way to write an interpreter for the 
> PDP-8.  It would be much easier if you just pretend it's an 8-bit 
> machine, and do 8-bit arithmetic, and 16-bit double precision, just as 
> was done in the 6502 interpreter.

I suppose there could be a code advantage in splitting things up like
that, but I don't see much of a in-core storage advantage, unless you
pack, for example, 3 variables in 4 machine words (in which case, the
code could get fairly messy).
 
> A fairly naive implementation should suffice for most of the early V1-3 
> games.  Once those are running, add swapping of impure data, and you'll 
> be able to run larger games.

Sure... adding impure swap would make the larger games fit, at what might
be a hefty performance penalty - but it should work.

-ethan

-- 
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Ethan.Dicks at usap.gov            http://penguincentral.com/penguincentral.html