Re: A82: Re: need info on VAT
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Re: A82: Re: need info on VAT
The problem is that the shells (both ASH and CrASH) are not VAT compatible: when
they run a program they reallocate it and in the same time... mess the memory
up!
Theefore it is quite hard to manipulate the VAT. The idea is to undo what the
shell has just done: you deallocate your own program. To do that you have to run
a sub routine that isn't affected by the allocation: a routine in APD buffer for
instance. You launch the routine that do exactly the same thing than the shell
when deallocating and the routine find the new address of your program.
Obviously, your program shouldn't use absolute address anymore (see Zshell
progs). Once you've done with the VAT you need to do exactly the contrary
thing. The only advantage is that you can call KEY_HAND instead of CR_KHAND.
To access the VAT itself it is nearly like on the TI83 but the ROMCALLs are
undocumented and not a lot tested...
Even if it may seem hard you must that some programs already exit: PJ82 and
orzunoid (both for ash and by sam Heald, i think).
The next version of CrASH should not have all those problem, being VAT
compatible. Unfortunatly it may take a very long time before it is released.
Eric
On Fri, 10 Nov 2000, Roger Levy wrote:
>
> thanks. so how do i access the vat? heres what i want to do: I wrote a
> tileset editor and want to be able to save multiple tilesets. i guess i
> should save them as protected programs with small t's to indicate they are
> tilesets. So how do i create new variables and also how do i scan the vat
> for tilesets so they may be loaded? is there a set of routines out there
> that can do these things for me?
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