[Coco] Quick 6809 Q for night owls in the US

[William Astle]

On 14-04-15 08:16 AM, Mark McDougall wrote:
> On 16/04/2014 12:04 AM, Mark McDougall wrote:
>
>> It's late here, and seeing 'dex' in Boisy's Liber809 blog had me really
>> confused because I couldn't find it in any instruction set listings...
>
> Hah! The 'dex' was actually in the 6502 portion of the listing - I used
> it thinking it was 6809 and turns out it was actually supported on the
> AS6809 assembler for '6800 compatibility'!!! :O
>
> How's that for dumb luck!?! ;)

There's a whole list of such instructions described in the Leventhal 
book which explains how "the 6809 assembler supports this instruction 
for compatibility with XXXX. It assembles as ...." That said, most 6809 
assemblers I've encountered do not support those compatibility 
instructions, though. (EDTASM certainly doesn't so it's unlikely code 
for the Coco uses those compatibility instructions.) Assemblers that 
support macros (like lwasm) can be convinced to fake it by defining 
appropriate macros.