On Aug 27, 4:51=A0pm, "Michael J. Mahon"  wrote:
> mdj wrote:
> > On Aug 27, 2:22 pm, "Michael J. Mahon"
 wrote:
> >> mdj wrote:
> >>> On Aug 27, 11:36 am, BLuRry  wrote:
> >>>>> For sending, anything over 4 cycles won't work,
so receiving is
> >>>>> probably moot. =A0(Oh, and 65C02 instructions are
illegal. =A0;-)
> >>>> You say that a lot about 65C02, but the target in
this case IS a //c
> >>>> after all. =A0:-D =A0 I think that in this one case
it's a forgivabl=
e
> >>>> sin. =A0But, as you say, if 6 cycles is too slow then
the serial por=
t
> >>>> idea is a non-starter. =A0Oh well, it was worth a shot!
> >>> Given that STY,STX,STA are also 4 cycle instructions
there's no need
> >>> for STZ in this case. All one has to do is ensure
> >>> one of the index registers contains a zero in critical part of the
> >>> polling loop, which is probably not a big issue.
> >> Actually, it's a killing issue, since all registers are busy.
>
> > Right. As someone who is used to C02 rather than 02 programming, I'm
> > finding on my current project (which must run on all II's) the
> > occasional annoyance with this. Since I'm so used to being able to do
> > ZP addressing without an index, I find PHP, LDX #00, ... , PLP a
> > common idiom in my current code :(
>
> Yep, the "index-free" indirection is one of the handier parts of
> a generally lackluster set of "C02" extensions.

I tend to refer to them as the 6502 "orthogonalisers" since STZ,TSB
and TRB are the only 'extensions' and they certainly lack lustre :-)

Matt
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