Re: Reading Joystick Position

[Andy McFadden <fadden@fadden.com>]

Joel <joelbuckley54.nospam.@hotmail.com> wrote:
> Alternately you could rewrite the paddle read routine to read them both
> simultaneously.
> The code is pretty tight now, so you might lose some resolution on a double
> read routine
> (maybe only 128 values instead of 255).

There's a routine in the Apple II Arcade Games book by (I think)
Jeffrey Stanton that did exactly this.  At least, I remember typing
it in and playing with it.

If memory serves, the resolution was in fact reduced.  Might not need
to be on a IIgs, but I can't remember exactly what the GS did.  (I
think the ZipGS had an optional slow-down feature for joystick reads.)

Random bit of trivia: my high school had a bunch of networked Apple IIs
with a "secure" mode to keep students from tampering.  They let the
students use Applesoft, but loaded it into the language card and zapped
anything that would touch a memory address and put the machine back into
ROM mode.  PEEK, POKE, CALL, WAIT, and some others.

My brother told me they left a back door.  I stared at an Applesoft
keyword chart until I remembered that the PDL() function didn't do
range checking.  Sure enough, that was the trick. :-)

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