Re: ROM cross-locator idea (was: Re: Tester(s) needed for PET Zork)

From: Andre Fachat (
Date: 1998-12-18 11:16:35

Larry Anderson wrote:
> Make datafiles of all the various ROM contents, then with a cross-locator
> program; plug in an entry point and what ROM it is from and then make the
> locator match the code (by scanning up say 5 to 30 'command' bytes and finding
> suitable matches on the other 'ROMs') thus find the alternate ROMs' entry
> points.  I've converted programs with this very method manually but I don't
> have the space to have two different model PETs side-by-side running Supermon
> to do the searches...
> Comon now, this shoud be a cinch, any takers?

Why not make a "binary diff" right from the beginning? With the diff
listing at hand it should be quite easy :-)

Anyway, another idea: using my "o65" relocatable fileformat you could
use undefined labels (like "BSOUT" etc - ok, BSOUT is a bad example :-)) 
and let them be relocated by the program loader, that then knows the 
addresses for the different ROMs. 
(That loaded could be loaded first, to check the ROM (probably the
disk drive for speeders as well), and then load and relocate
the real program appropriately.


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Andre Fachat, Institute of physics, Technische Universitšt Chemnitz, FRG
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