Date   : Fri, 31 Jan 1997 18:00:59 +0000 (GMT)
From   : Mark Cooke <mpc@...>
Subject: Re: BBC Master 128 Emulators???

On Fri, 31 Jan 1997, Robert Schmidt wrote:

> michael inch wrote:
> > 
> > Does anyone know if there is such a thing as a BBC Master emulator???
> > 
> No, none exist, and I think I can safely say that there's nothing you 
> can do with existing emulators to make them behave as a Master (then 
> the community would have known by now).

I thought that the Archimedes based emulator by Mike Borcherds could 
emulate a Master, along with the Electron and Beeb B.

The Master has a number of extra intructions (PHX, PHY, PLX, PLY, etc), 
and of course the extra support for shadow ram, and the extra ram up 
around D000 (if memory serves).  Accessing the CMOS configs is fairly 
easy and is partially documented in the info on the Master Mike and I put 
together, and that is available from the web site.

> Does anyone (authors?) have any idea of how difficult a Master is to 
> emulate?  What's more difficult than a model B?

In terms of 'more difficult' then nothing much. The Master should run 
quite happily with a standard DFS/XDFS etc, though it was built around a 
different disk controller than the Beeb-B (1770 rather than 8271)

Mike's emulator shows it's achievable, and as I recall, he had the Master 
part of his emulator going fairly soon after starting to add it to the 
basic structure.

Regards

Mark

Mark Cooke                  The views expressed above are mine and are not
Systems Programmer          necessarily representative of university policy
University Of Birmingham    URL: http://www.sr.bham.ac.uk/~mpc/