Re: A92: Rom dump? ATTN: Shawn Prestridge


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Re: A92: Rom dump? ATTN: Shawn Prestridge




At 03:13 PM 1/15/98 -0600, Shawn A. Prestridge wrote:
>When they say "Rom Dump", they mean a backup of the 92.

Actually they mean a one or two megabyte image of the actual ROM...

>There are 12 versions of the 92 in the US,

Is this really true? I've never seen or heard anything about ROMs 1.1, 1.6,
or 1.9. Do these versions exist? If they do, were they ever released?

>In a nutshell, what Fargo does
>is play off of a bug in the 92 GraphLink software.  David Ellsworth
>figured out that if he did a backup of his 92, and then stuck
>some machine code at the end of it, he could send the whole
>thing to the 92.  When the 92 hits the end of memory, it starts
>overwriting the first sectors of memory, which allows him
>virtually unlimited access to all areas of the calculator

Actually, Shawn, I don't use that method anymore :) I've been using an
alternate, much cleaner method for quite a while now. It takes advantage of
the fact that the memory in a backup file intersects with a global event
handler callback variable that the TI-92 OS uses. Whenever a GUI event
occurs, it reads this variable and calls the routine to which it points.

> - some of which we really wish he didn't!!

I'm curious, how did four object files and a smidget of C code get into the
ROM 2.1 image? The object files are aptabled.o, dialog.o, graph3d.o, and
win.o. The C code is probably from lists.c or something. When I found it, I
came up with two theories: 1) that it was a present from some anonymous
employee(s) at TI, and 2) that it was a mistake caused by uninitialized
memory that somehow got past everyone and ended up in the released ROM.

Also, does TI plan on using the Line-F exception on the 92plus? I'm
thinking of using it for Fargo II, but I wouldn't like to conflict with
anything the 92plus does.

If you're not allowed to answer either of those questions, I understand.
But if you *can* answer either or both of them, I would appreciate it very
much. :)

---
David Ellsworth
davidell@earthling.net
IRC: eXocomp
ICQ: 2300673


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