Date   : Tue, 02 Aug 1994 10:00:06 +0100 (BST)
From   : amh15@... (Alan Hart)
Subject: Re: your mail

> > For what it's worth, you will need some data other than this stuff - and you
> > will have to store it in the PC's RAM. Thus you will almost certainly need
> > another segment (ES). Unless you store stuff in the Code Segment.
> 
> What other stuff? I can't really think of anything. It would be easy to 
> stick stuff in the code segment, though.

Well, what about things like:

- context of the 6522 (internal registers, etc.)
- context of the video hardware (6845, ULA registers)
- possible copy of BBC or PC screen map, depending on how you implement it

Although the first two are memory mapped devices, they occupy only a byte or 
two each. You have to select which register you're talking to using one 
address and read/write the data using another. Hence you can't just use the 
BBC memory map for this because several things occupy the same address.

Alan

 Alan Hart  -  amh15@...  -  University of Cambridge, UK