Re: A85: ROM Browser


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Re: A85: ROM Browser




My suggestion would be to have a program that traces what occurs in ROM
when you are running the TI-85 emulator.  You could therefore see where
in ROM the calculator goes upon the execution of a particular BASIC
command or any routine for that matter.

Ben

Dines Christy Justesen wrote:
> 
> The program you suggest would probably find most functions, but I am not
> sure whether it would be very useful. The problem is that only a small
> part of what is stored in the system mem has been descirbed. A lot of the
> function which has not been desriebed yet uses many of these addresses,
> which makes it very hard to understand what they are doing. Most of the
> Basic functions consist of almost nothing but calls to unknown functions,
> which makes it even harder to understand what they are doing. So unless
> you have an idea of what the function might be doing before you start
> disassembling it, it is almosty impossible to find out what it does.
> 
> Using a program like the one you are suggesting would return a lot of
> functions, and it would be very hard to figure out which of them to have a
> look at. Some of the functions the program would find would probably be
> disassembled data, which makes no sense.
> 
> My suggestion to anyone who wants to find functions in the ROM is
> therefore to use other methods to finds the functions to disassemble. If
> you know what kind of functions you are looking for it is normally not
> hard to find the area where they are placed.
> 
> Dines
> 
> __________________________________________
> 
> Dines Justesen
> Email: c958362@student.dtu.dk
> WWW  : http://www.student.dtu.dk/~c958362/
> __________________________________________
> 
> On Thu, 24 Sep 1998, Humberto Yeverino wrote:
> 
> >
> > When I said just look for ret intructions I hadn't put a lot of thought
> > into "routine finding."  I can still be done of course.  Any non
> > conditional jp or ret that can't be bypassed would mean the end of a
> > function. Ex:
> >
> > TI_MUL:
> > ld a,(hl)
> > ...
> > jr z,Overflow
> > add a,24
> > ret
> > Overflow:
> > ret c
> > ld a,0
> > ret
> > *FUNCTION ENDS HERE*
> >
> > My previous method seemed a little too simple.  So my current method would
> > be scan for absolute rets and jps, if a conditional jr or jp is
> > encountered, follow it only if it jumps forward, continue searching for
> > absolute jps and rets...
> > I don't think I overlooked anything this time.
> >
> > I would write a program like this but I've got lots of work, and midterms
> > are coming up.
> >
> > later,
> >
> > -Humberto Yeverino Jr.
> >
> > "I kick ass for the Lord."
> >
> > ***********************************************************
> > Home Page:
> >   http://www.engr.csufresno.edu/~humberto/Home.html
> >
> > Ti Page:
> >   http://www.engr.csufresno.edu/~humberto/tex.html
> >
> > z80 Source Page:
> >   http://www.engr.csufresno.edu/~humberto/z80source.html
> >
> > Official Tyrant Home Page:
> >   http://www.engr.csufresno.edu/~humberto/tyrant.html
> >
> > E-mail:
> >   humberto@engr.csufresno.edu
> > ***********************************************************
> >
> >


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