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Re: Apple III info wanted
In article <3lhvtt$fvv@vixen.cso.uiuc.edu>,
Jim Wong <jd-wong@uxa.cso.uiuc.edu> wrote:
> gbohling@herbie.unl.edu (Tiresias) writes:
> >"Processor: Based on the 6502B microprocessor, with extended addressing
> > capability
>
> How does "extended addressing capability" work?
I don't know exactly. It is implemented by extra hardware that
monitors the operation of the processor. I believe it involves
extensions to some addressing modes.
One that I remember hearing about (many years ago, so I may have the
details wrong) is that (indirect,Y) instructions in a certain range of
zero page addresses will fetch a third address byte.
Any Apple III programmers out there?
--
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand