[Coco] 6309/6809 opcodes with mixed 8/16 bit registers

[Darren A]

On Sun, Nov 18, 2012 at 3:32 PM, Harry Hurst wrote:
>
> 1> Does the 6809 just execute an effective NOP on an illegal opcode? Or
> does it decode the illegal opcode as a nearby opcode?
>
> 2> Does anyone have any info on what would happen if a 6x09 would execute
> opcodes like TFR or EXG with mixed 8 and 16 bit registers specified? Do
> both the 6809 and the 6309 behave the same in this case?
>
> 3> What happens on the 6309 when it has mixed 8/16 bit operands on the
> ADCR, ADDR, ANDR, EORR, etc.?
>
> 4> Do invalid indexing modes also trigger the invalid opcode trap on the
> 6309?
>

Go to this web page:
<https://sites.google.com/a/aaronwolfe.com/cococoding/home/docs>

Download the document titled "6x09_Instruction_Sets.pdf".  This has
answers to all of the above questions.

Darren