[Coco] MAMOU bug?

[Juan Castro]

In all the 6809 programming I did, I never used U as a stack pointer.
It was just a third index register.

On Thu, Jan 24, 2013 at 4:20 PM, Steve Bjork <6809er at srbsoftware.com> wrote:
> The pshu s is legal.
>
> This command assembles to $36 $40.
>
> What is illegal are pshu u or pshs s since the same bit (B6) in the post
> byte is used to flag the same register.  (S/U)
> (If pushing on the System Stack, then push the User Stack.)
>
> My games used the U register to point to the game object and was pushing and
> pulling all the the time.  Yes, my games were written in assemble but in a
> type of object oriented design.
>
> Steve
>
>
> On 1/23/2013 5:43 PM, Gene Heskett wrote:
>>
>> On Wednesday 23 January 2013 20:35:12 Willi Kusche did opine:
>> Message additions Copyright Wednesday 23 January 2013 by Gene Heskett
>>
>>> Hi!
>>>
>>>      I get an error when I try to assemble " pshu s".  The error is
>>> "illegal register name".
>>>
>>> Willi
>>>
>> Its legal code Willi, but maybe its trying to tell you to aim a little
>> farther forward than your toes, cause I can't think of a better way to
>> take
>> careful aim and make the machine crash.   Regs.u and regs.s, unless you
>> are
>> a master programmer, doing 100% of your own housekeeping, are pretty much
>> only for the OS's use, not the programmer.
>>
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>>
>>
>> Cheers, Gene
>
>
>
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