Re: A85: ROM Browser

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Re: A85: ROM Browser


If you start pasting the code from all the functions which a function
might call, the source end up being extremely big.

The ROM is that messy. Data is stored in a lot of different places in the
middle of code. (Have a look at FIND_PIXEL)

Dines
__________________________________________

Dines Justesen
Email: c958362@student.dtu.dk
WWW  : http://www.student.dtu.dk/~c958362/
__________________________________________

On Thu, 24 Sep 1998, Humberto Yeverino wrote:

> 
> On Thu, 24 Sep 1998, 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.
> > 
> Couldn't you then just convert all calls in a function to source?  Putting
> a comment on the side like "from $123F".  The code would then be more
> readable.  Since, as you say, most routines just make calls, you could
> find and several functions at once by examining each function one by one.
> 
> The program would definitly have some sort of database to keep track of
> routine addresses and the names you assign them.
> 
> > 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. 
> > 
> The way I imagine using a program like this is browsing though routines
> until you find something that makes sense.  You give it a name and little
> by little other routines make more sense.
> 
> So maybe the best way would be to define the short routines first, give
> them names(labels whatever) and then the bigger routines will be easier to
> read.
> 
> As far as interpreting data as code, ROM can't be that messy, I mean when
> we write asm programs we put data in one place, routines in another..
> 
> > 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
> > 
> It would also have some sort of search, where you could search for
> instructions, like FIND: "call GET_KEY" or some other function you've
> named.
> 
> > On Thu, 24 Sep 1998, Humberto Yeverino wrote:
> 
> > > 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'm sure this question has been asked before but doesn't TI have extensive
> documentation on 85 ROM routines and thier locations? I would think
> that they would have to.  Has anyone tried asking TI to make that
> information public?  It seems like were putting a lot of effort into
> finding out what they already know.
> 
> -Humberto Yeverino Jr.
> 
> "I kick ass for the Lord."
> 
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