A83: Re: Re: Re: Re: Re: TI coding skillz
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A83: Re: Re: Re: Re: Re: TI coding skillz
I actually haven't checked, but I'm willing to bet that the reason it
displays incorrectly is because when the text display routine is called, the
$0C page is switched out, and another page (with the text display routine on
it) is switched in. So the pointer to the text is now a pointer to some
random stuff on the new page, which is displayed. TI-83 Plus applications
have this same issue, the solution is to either copy to the text to RAM, or
have a text display routine in your app.
-Dan Englender
----- Original Message -----
From: "David Phillips" <david@acz.org>
To: <assembly-83@lists.ticalc.org>
Sent: Wednesday, November 29, 2000 5:23 PM
Subject: A83: Re: Re: Re: Re: TI coding skillz
>
> The program starts at $52e9 on page $0c on ROM versions 1.07 and 1.08.
> Viewing the dissassembly in VTI, it appears to be correct for the code's
> location (i.e. all the call's and ld's match up). I tried bcalling it
from
> an ion program, and the first line of the character test works, but when
it
> gets to the part where it should display "press enter", it prints a bunch
of
> random characters and crashes. HL points to the correct text beforehand,
> and the string is null terminated, so it should work. My guess is that it
> has to do with ion doing weird things with memory. But since I have never
> programmed the 83, I have no idea. I tried making a "normal" Send(9"
> program, but couldn't figure out how to actually make it work. Anyone
care
> to explain that?
>
> > I took a peek. I found the code and text, and it is on page $0C, which
is
> > the ROM entry point page on the 83. My guess is that TI had a bunch of
> left
> > over space on this page, so just stuck the sample stuff on at the end,
> after
> > the entry point call table. I'ven't a clue whether there is actually
any
> > way to access this from the TIOS or whether it's just sitting around in
> the
> > ROM, though I'd guess the latter. I wrote a program to check if the
same
> > code was anywhere on the 83 Plus, and the text "cool" never appears
> anywhere
> > in the TI-83 Plus's ROM. Of course, there could be something else
> > altogether hiding in there...
>
>
>
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