[Coco] Any reason to put a 6309 in a Coco2?

[Arthur Flexser]

That was different--a typical example would be LDX #xxxx, where the xxxx
would itself be a two-byte legal instruction that you could safely jump to
but which would have no effect when executed as part of the dummy LDX--a
nice trick for saving bytes in a ROM where space is tight, and hardly
something you'd call "notorious".  No illegal opcodes involved.

Art

On Thu, 1 Jan 2004, Neil Morrison wrote:

> 
> Interesting. Microsoft was notorious for doing this with their ROM
> Basics.
> 
> Neil
> 
> ----- Original Message ----- 
> From: "Arthur Flexser" <flexser at fiu.edu>
> 
> 
> > I ran into one incompatibility when I installed the 6309, though it
> was
> > only because the software author broke the rules.  He used an EXEC
> in his
> > Basic program that was to an address in the middle of an
> instruction, but
> > which worked okay with a 6809, which ignored the illegal opcode.
> The 6309
> > vectored this to its "illegal instruction" error handler, which
> hadn't
> > been initialized with any code to handle errors, so the program
> crashed.
> 
> 
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