Date   : Thu, 27 Apr 1995 11:59:26 +0100
From   : lamcw <lamcw@...>
Subject: Re: CurrentStateOfMyEmulator

Hi all,


Mike B wrote:

;o Runs the original unaltered OS 1.2 ROM
;o Superb sound emulation
;o Full filing system (*SPOOL, *EXEC, OSGBPB etc),

Cool, my em has some hooks in it cos I was too lazy to do the
OS file routines properly. Sound as well? Can you post some details
about how you did it? I'd be very interested!! ;-)


;o Mid-screen mode/palette changes (maybe)

You need this for Elite... doe this mean Elite only partially works on
your em?

Thinking back, the way I emulated the CRTC was not as well as it could
have been. It works but I should have done it the way a microchip would
do it.


;NB "Unused" Opcodes are defined to be NOPs
;   The extra Rockwell opcodes are not supported

Arrrgh! Dreaded undocumented opcodes! This topic will surely be THE
major sticking point for all our 6502 emulators. I have 2 sources
but they are far from thorough. Maybe we ought to get a good thread
going about this subject.


I've put MBE on hold for the moment as I'm working on another 6502
emulator (this time the Atari 400/800). 

Best wishes,


Chris Lam,
Aston University,
U.K.