Date   : Thu, 27 Apr 1995 13:00:46 +0100 (BST)
From   : Mike Borcherds <borchrds.teaching@...>
Subject: Re: CurrentStateOfMyEmulator

> ;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!! ;-)

A friend of mine wrote the sound, so I don't know much about it.
However, I can reveal how Superior's Speech! works - it puts the
chip on very high frequency and wiggles the amplitude.

I have a small filing system ROM that uses opcode 3 followed by
another number to tell the emulator which filing system routine it is.

I'm still thinking about how to pass information from a *. back
into the emulator

> You need this for Elite... doe this mean Elite only partially works on
> your em?
It has a hack to make elite work :)

> 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.
my screen stuff is written for speed - doing it "properly" would be 
very slow, I think

> 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.
No, because most games ran on the Master, which has a 65C12, on which
undocumented opcodes are defined to be NOPs
Zalaga is the only game I know of that uses them





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