[Coco] 6809 Push/Pull

Lee leep at tigerbase.com
Sat Jun 6 00:02:13 EDT 2020


I did a quick Google search and this article seems to cover it pretty
well.  https://silicon-heaven.com/howel/parts/6809_instruction_set.htm

It looks like registers (on a single PSHS/PSHU) are pushed in the order PC,
U/S, Y, X, DP, B, A, CC.  They are PULS/PULU'd in the opposite order.

So if you did PSHS X,Y it would push Y first, then X.  If you did PULS X,Y
it would pull in the opposite order, X first, then Y.

-----
Lee


On Fri, Jun 5, 2020 at 9:44 PM Salvador Garcia via Coco <
coco at maltedmedia.com> wrote:

>  Adding to this thread...
>
> Is the developer allowed to do some thing like:
>
> PSHS    X
>
> PULS    Y
>
>
> What if I try something like this:
>
> PSHS    X,Y
>
> PULS    X
>
>
> Like others, just curious. :-) Thanks, Salvador
>
>
>
>
>     On Friday, June 5, 2020, 03:10:58 PM CDT, Arthur Flexser <
> flexser at fiu.edu> wrote:
>
>  The order of registers in PSHS and PULS is a fixed property of the
> processor.  PSHS X,Y and PSHS Y,X generate identical opcodes, so it makes
> no difference which you use.
>
> Art
>
> On Fri, Jun 5, 2020 at 4:06 PM Jim OKeefe <jimokeefe39 at gmail.com> wrote:
>
> > For all you ML gurus out there.
> >
> > PSHS    X,Y
> >
> > To return registers to their original values is the correct pull
> >
> > PULS      Y,X
> >
> > Or
> >
> > PULS      X,Y
> >
> > Thanks Jim
> >
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> >
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