[A85] Re: Running assembly programs
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[A85] Re: Running assembly programs
> Van: Dines Justesen <dines@aub.dk>
>
> The BASIC program copies the contents of a var to a var which has been
> moved to the system mem. This causes the pointer to the routine executed
> after the next keypress to be set to the location of the shell (the shell
> is the first program in user mem which means that it is never moved by
> the TIOS). When the BASIC program returns the keypress function is
> called using the modified pointer which executes the shell. The shell
> reset the pointer to the original value and the memory is now ok again.
> The shell then finds all programs in the VAT which has the correct
header,
> and displays a list of them. Once the user quits the shell it returns to
the
> caller and the TIOS returns to the prompt.
>
> Deleting the var mapped to system mem will cause problems, other than
> that the mem is ok.
Thank you, I have found this out already. This is a very sleepy mailinglist
so I haven't reported that, I didn't suspect anybody to answer the mail. I
just wanted to know if thing weren't like with SOS (Ti83), where the VAT
pointer weren't updated. Could be that when executing the hack the TIOS
first got a little 'berzerk' (doing strange things in mem) and in such way
'accidentaly' (but planned) ran some code in RAM.
As far as I understand you can let this pointer point to anywhere in memory
when using a 'two var' solution (one with addapted pointers, and one with
addapted content). And with a 'one var' solution, you can change the
pointer to any hex-value possible to create with FP system (BCD) used by
the Ti's.
Henk Poley <><