Date   : Wed, 15 Feb 1995 17:17:18 +0000 (GMT)
From   : Neil Pollard <pollard@...>
Subject: Emulating I/O

Dear all,

I am a fairly new member to the mailing list and wondered if anyone could 
help me with a few problems. I am not actually emulating a beeb, but 
writing a 6502 emulator for my 3rd year CS project (using C on a Linux 
system). However, I figured trying OS1.20 would be a good way of testing my 
code.

Firstly, I think I should get away with only emulating some bits between 
FE40 and FE4F as far as I/O goes, but how much of this will I need to
do to get
as far as the startup message? I haven't done any interrupts as yet either.
At the moment, I'm intercepting OSWRCH to get character output, but I'm 
only getting odd bits of rubbish through, although that may well be due 
to bugs of my own. I've also left BASIC permanently mapped in at 8000 - 
any ideas whether that might cause problems later?

If the job is going to be too much hassle, I will have to forget about 
the OS for the time being - deadlines are looming :-( If this is the 
case, I would be grateful is anyone could point me in the direction of a 
few 'generic' 6502 programs, so I can see if my code is okay.

Thanks,
Neil

P.S. I've had a play with David Gilbert's emulator and I'm very impressed.