[Coco] CoCo DECB error list and descriptions

William Astle lost at l-w.ca
Wed Feb 14 10:06:34 EST 2018

On 2018-02-14 04:05 AM, Lee wrote:
> Well, then maybe my attempt to do something simple backfired.  I'm just
> beginning to try to re-teach myself 6809 assembly (I knew it 35 years
> ago).  Is it possible to return back to DECB from ML that you EXEC from
> DECB (this is purely educational)? The "?FE ERROR" was a result of a truly
> rooky mistake, I left off a PULS A at the end.  But fixing that just caused
> it crash hard.  I was trying to see if I could just RTS at the end, but
> that caused it to crash and lock.  I'm guessing maybe EXEC doesn't push a
> return address that will cleanly return to DECB?  Maybe there some DECB
> routine I need to JMP to at the end?

You do only need an RTS at the end. Unless you're trashing DECB's 
variables in low memory or clobbering the stack.

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