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

[Arthur Flexser]

$3E definitely does a reset on the 6809.  I recall using an assembler
(MAS?) whose manual noted that the assembler would recognize RESET in
your source code and assemble it to a $3E.

On a 6309, though, $3E gets you dumped onto the illegal opcode vector address.

Art

On Thu, Nov 22, 2012 at 10:57 AM,  <jdaggett at gate.net> wrote:
> Not sure if you have the undocumented opcode in on the 6809, opcode $3E.
>
> On all the official opcode maps it does not appear. If I remember correctly it will do a
> RESTART ( ie reset). The term RESTART appears in the programming manual from 1983
> as a hardware interrupt, (ie RESET). For some reason they added a software reset or
> RESTART that never made it to the official documentation.
>
> You can check it out by inserting into any code
>
> FCB $3E
>
> and see what it does.
>
>
> >From the old 6800 days there was HCF opcode that I am not sure translated into the 6809 or
> not. Rumors has that it did. In the 6800 it was $DD. Not sure what it was in the the 6809 or
> even if it ws still there. $DD is STD in direct mode in the 6809. HCF or more commonly know
> as Halt and Catch Fire. It actually did not catch fire but the processor went into an address
> self test mode that had to be hard resetted to continue. There maybe other test mode
> opcodes that may or may not be there. Some may appear to do nothing but actually do
> something. The HCF opcode turns the address bus into a 16 bit counter. There maybe even
> one for the data bus. I know that 6811, 6805 and others based on those two have built in self
> test modes that are used in the testing of the die before and after packaging.
>
>
> james
>
> On 21 Nov 2012 at 6:54, Harry Hurst wrote:
>
>> I see what you mean, Luis. Chris got everything right, as far as I can
>> see, up until page 7. That table on page 8 is a bit of a mess, though. I
>> understand how he could easily have made that particular mistake, that
>> opcode looks out of place in its proper position.
>>
>> I have been looking at 6809 undocumented addressing modes, and have made
>> up a table in a spreadsheet file. I am attaching it to this post.
>> Hopefully, I will not have made any similar mistakes. There are two sheets
>> in the file. The first is basically a duplicate of Darren Atkinson's
>> opcode table. The second is the addressing modes table. Please let me know
>> if I have made any errors.
>>
>> HH
>>
>>
>>
>> > LDQ = CD , not exits, instead there  STD, wrong
>> > And other more errors
>> > So in other documents.
>> >
>>
>
>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco