[Coco] Re: Any reason to put a 6309 in a Coco2?
bradgrier at cox.net
Thu Jan 1 22:06:14 EST 2004
Torsten Dittel wrote:
>>Interesting. Microsoft was notorious for doing this with their ROM
> I think the opcodes in Microsoft BASIC weren't illegal, they just did
> something useless. AFAIR some of the so called "illegal" instructions of
> the 6809 had some effects on the registers including the CC which just
> didn't make sense. I once saw a list somewhere were all the "functions"
> of those opcodes were listed. I wonder if the emulators do this well.
> Tim? Brad?
There's some documentation for the illegal opcodes at:
I believe I implemented just one or two of them in Mocha in order to get
a specific game to work. I probably should add all the ones that make
sense - I think I was worried about performance.
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