Re: LZ:83 ASM
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Re: LZ:83 ASM
On Tue, 3 Sep 1996, Rob Taylor wrote:
>
> > I disasembled the _IPOINT routine but what I found doesn't make
> > any sense. It could be a mistake on my part but I was fairly
> > careful. It could be a mistake in TI83ASM.INC from TI. Their
> > keycode chart got all the key codes wrong so that wouldn't
> > surprise me, or it could be a bug in my hex viewer, which would
> > surprise me a little, but not a lot. I suspect TI but I'm not
> > sure of that. I didn't have time to check any further today.
> > I may tomorrow. I will if I can.
> >
> > Here's what I got:
> >
> > The entry 4AE8 goes into what is appearantly a jump table
> > with 4 byte calls and returns. This entry is
> >
> > 4AE8 CD9133 call 3391
> > 4AEB C9 ret
> >
> > 3391 CD8B2E call 2E8B
> > 3394 C9 ret
> >
> > 2E8B E5 push hl
> > 2E8C E5 push hl
> > 2E8D F5 push af
> > 2E8E D5 push de
> > 2E8F E5 push hl
> > 2E90 210B00 ld hl,00B0
> > 2E93 C9 ret
> >
> > Which should crash the calculators. Maybe it does.
> > When I can I'll double check my work and write something
> > that calls _IPOINT and see if it works and is really at
> > that address. Of course I've reversed the addresses for
> > readability.
> >
> hmm.. how do you fancy making a complete rom download? do you have
> any ideas on how the rom paging works (b i would hope that it's the
> same as on the ti 85 (i.e. port 5 sets the bank to appear at
> 4000-8000) but in view of teh obvios hardware differences and the
> wide use of adddresses of $4000 onwards, this seems unlikely.
I thought of rom paging but I couldn't find any information
on the rom size in www.ti.com or ticalc.org. Also, nothing
in the above code looks like it would initiate a bank switch.
I went through the same procedure 2 more times, very carefully
with the same results. I also did some more careful testing
on my hex viewer, on the only part of ram that's known to me,
the viewer itself. Everything looks ok.
In order to do a rom dump, I think I need to access a string
to write the dump into it, but I haven't been able with many
many tries to get a good result from their call to get the
address of a string. I'm not sure if it's incorrect docs or
if I just don't understand something correctly. They don't
explain it very well and their sample code doesn't give any
examples of this.
I haven't tried using _IPOINT recently but I think I did when
I first got the calculator in a little quicky test program to
just put a pixel on the screen. I may be thinking of something
I did on the 48 or my M100 though.
I haven't given up. I'm still fiddling with it as I have time.
I'll probably do something to turn on some pixels in a few days.
If you know that bank switching is going on, that would be
useful info. If you even know if the rom is bigger than 32k
that would help. Although that doesn't seem to be going on here.
Barry
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