LZ: Re: Ash, an ASM shell for the TI82
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LZ: Re: Ash, an ASM shell for the TI82
If have collocted most of the question about ASh, i could find on lz and
i have
tried to answer them all below.
Richard wrote:
> Is this for real or just a hoax?!?!
This is definetly for real. The shell will be released monday.
Mark G Malley wrote:
>
> I must have missed it, but are you saying that you can do limited asm on
> the 82? Thanks!
Depends on what you mean by limited. Ash allows you to make asm programs
on the
TI82, like Zshell for the TI85. Currently i can not think of anything
you can
do in a Zshell program which you can not do in an Ash program.
Michael wrote:
>
> Will the shell be zshell compatible?
To make it easier to port program from the TI85 to the TI82 we have
tried to
make everything as Zshell like as possible, but because of the
differences in
hardware changes have to be done programs before they can run under Ash.
Michael Wyman wrote:
> > Will the shell be zshell compatible?
>
> No. A few reasons... Screen size is different, for one. Certain ROM
> calls would be different, though it is possible that this could be
> accounted for in the shell... But one major thing (Correct me if I'm
> wrong.. I'm not _absolutely_ sure about this..): The TI-82 does not have
> string Variables, so programs have to be stored in some other way.
The screen size is different, and it is not memory mapped. The TI82 does
not
have strings, but it has program whic are just as good. That Ash uses
programs
and not strings is no problem.
Will Stokes wrote:
>
> I can't belive nobody has asked the eternal question, how that hell do
> you access the shell? Somehow you modified the backup file.I'm very
> interested in this. there is no custom menu, so how do you start the 82
> asm shell? Will zshell games work on it? Is there any way I can see a
> beta? please? I do make asm games ;)
The method used by Ash was actually discussed on lza almost half a year
ago, and
someone mentioned it not long ago on lz.
The TI82 system has a special function in the begining of page0 which
handles
keyboard input, to take care of special keyboard functions obly needed
in a few
places in the system it calls another function based on a pointer. So
every
time a key is pressed the function will read a byte and a word from the
ram
which contains the rompage and the adress the call. By changing the word
to a
pointer to an asm program in the ram one can make the calc execute
program
simply pressing a key.
The problem with all this is that this pointer is not stored in 82b
files. By
changing stuff in the VAT, it is possible to set the pointer to the
needed
value if you store one var to another. The problem here is that the TI82
only
has a limited number of vars, so taken two vars of the same type for a
shell is
a bit much. We have solved this problem by chaging stuff in the VAT
again. So
now the two vars will show up in memory menues, but you can still use
all the
vars on the TI82.
To make it easy to start the shell we have made a very small basic
program which
does all what is need to start the shell. So to start the shell you run
the
program, when it tell you to do so you press any key and you see the
shell.
when Ash is released a document called HACK82 (similar to david boozers
doc on
the TI85), will be released. This doc explains what to do and how to do
it of
you want to run asm.
Dines
--
_______________________________________
Dines Justesen
Email: dines@post1.com or
c958362@student.dtu.dk
WWW : http://www.gbar.dtu.dk/~c958362/
_______________________________________
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