[A82] Re: TI82 ROM Version 19.006

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[A82] Re: TI82 ROM Version 19.006


A lot of programs includes images. If a program, which is supposed to
translate ROM calls, is used on ones of these programs, how does is know
whether the byte it finds, which looks like a call is part of an image, or
code which is going to be executed? Try disassembling some code which
includes data, and see how that looks afterwards.

Dines
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 Dines Justesen             dines@aub.dk             www.aub.dk/~dines
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----- Original Message -----
From: "Dan Weiss" <dwedit@hotmail.com>
To: <assembly-82@lists.ticalc.org>
Sent: Thursday, July 05, 2001 6:22 AM
Subject: [A82] Re: TI82 ROM Version 19.006


>
> I don't think a single program exists that calls romcalls in any non jp
non
> call way.  No programs stuff a romcall into a pointer table then jump to
it,
> no programs self modify up a romcall from nowhere, the only way romcalls
are
> executed in practice is if they are explicitly called or jumped to.  Find
> one program that DOESN'T use conventional means (call, ROM_CALL, jp,
> bcall...) to call romcalls... good luck!
>
>
> >From: "Dines Justesen" <dines@aub.dk>
> >Reply-To: assembly-82@lists.ticalc.org
> >To: <assembly-82@lists.ticalc.org>
> >Subject: [A82] Re: TI82 ROM Version 19.006
> >Date: Wed, 4 Jul 2001 22:42:56 +0200
> >
> >
> > > Wouldn't it be possible to write a program to replace the rom_calls
with
> > > nops then the proper call, and change any JP's or CALLS to rom
addresses
> > > with the correct new pointer address?
> >
> >It shouldn't be too hard to write a program like that, which would work
for
> >most regular programs. The difficult part is to avoid chaning an data
which
> >might be included in the program. (It is not that easy to check whether
it
> >is a call to the ROM or some bits in an image used by the program). The
> >shell use selfmodifying code, and other things which would make the
> >translation harder. So for most programs it could probably be done, but
it
> >might be easier to just recompile them if the source is available.
> >
> >Dines
> >
> >
> >
> >
> >
>
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>
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