From: Marko Mäkelä (marko.makela_at_hut.fi)
Date: 2003-07-08 13:51:27
On Tue, Jul 08, 2003 at 04:09:08PM +0800, ncoplin@orbeng.com wrote:
> >It's not necessary to transfer the program to $801. Some Vic-20 cartridges
> >contain BASIC code that is executed directly from the ROM, by changing some
> >pointers ($2b/$2c might be enough).
>
> Nice trick ;)
>
> ...but what happens if you need variables? Do these always need to be
> "after" the program or can the end of basic text be left pointers be left
> pointing to the normal "no program vaules.
The $2d/$2e pointer points to the start of variables. As long as the BASIC
text is not edited, that pointer does not need to point after the start of
BASIC text pointer ($2b/$2c). The space for variables and strings resides
between ($2d) and one of the bigger pointers (52 or 56 decimal).
Marko
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