[A82] Re: TI82 ROM Version 19.006


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[A82] Re: TI82 ROM Version 19.006




> Van: Dines Justesen <dines@aub.dk>
>
> Making a shell which is able to update the VAT after relocating a program
in
> a way which means that these hacks are not needed is not easy on the
TI82. I
> know that both the Crash team and I have tried to do it, but ended up
with
> some strange problems. So while it is a good idea, and was planned for
the
> next major update of both CrASH and Ash, neither of us got it working
> properly.

What kind of problems? VAT being messed up, etc?

Are there big differences between the Ti82's and the Ti83's filesystem? If
these aren't there, than it's more a way of finding the adress equivalents
on the Ti82, and things will work (hopefully).

> > of instant-assembly-execution difficulties on the Ti82 you should need
a
> > graphical shell, but together they take up only about 1000 bytes (348
byte
> 
> It is posible to start assembly programs directly from the programs menu
on
> the TI82, but people seem too prefer having a shell. Should someone want
to
> make a shell which only used the programs menu, that would take up less
> space, and would not be much harder to do.

Nice, that is the advantage of Venus, the shell is very small and
everything get's a whole lot more transparent, always nice for the
people-who-don't-know-what-a-shell-is...
And the pro for the programmer is the bigger crash-resistance (if things
will work on the Ti82), plus you could use the same header for the Ti82 and
Ti83 (only different org-adress). Possibly Ti83+ can be added too, major
change will be execution of archived progs, but that has be been done
before by many shells/programs.

> > program loader (Venus), 508 bytes shell (Venus Explorer), and some
libs).
> > The program loader itself can be located inside the stack.
> 
> The size does depend on how nice an interface you want for the shell, but
> also what functions you include in the shell. IF you include more
function
> the shell will be bigger, but the programs smaller, so that is not an
easy
> decision. If both the currently supported ROM versions and 19.006 are to
be
> supported, the number of ROM calls which can be used without problems is
> very limited, so I shell would probably have to include more functions to
> compensate for this.

As I understand the Ti82 shells ASH and CrASH, have some built-in
pointers/jumptable which will point the call to the right location for the
different ROM versions. This is indeed not needed on the Ti83, but... Venus
has external libraries (in a better/other way then SOS), also just called
'externals'. You could could use these libs to straighten up some things,
but okay, it won't be compatible to (Cr)ASH.

BTW: We don't NEED to break with call compatiblity, it's just an option
which uses less memory...
BTW2: (Cr)ASH programs won't run, or won't have the 'improved
crash-protection', because of there org-adress...

	Henk Poley



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