On Aug 27, 2:22=A0pm, "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 forgivable
> >> sin. =A0But, as you say, if 6 cycles is too slow then the serial port
> >> 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 :(

Matt
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