Re: Looking for a really good PET zero-page map

From: Ethan Dicks (
Date: 2008-06-15 12:44:55

On Sun, Jun 15, 2008 at 10:05 AM, "André Fachat" <> wrote:
> Hallo Ethan,
>> What I was after the zero-page maps, though, was not for
> Would that help?

I've already gotten past the problem that the maps I had weren't helping with,
but that document does have more info about the locations below $11 that
were causing me grief (locations with the same name were safely reused
in the C-64 code, but are apparently used in less-well-documented ways by
BASIC 4.0.  Since C-64 and VIC-20 BASIC is nearly the same as PET
BASIC 2.0, it kind of explains the results I was seeing).

> If you have better ideas for links on this page:
> tell me please

I have that page up and will see what comes to mind.

>> What would be great would be a companion map that
>> would more-or-less show locations that were safe to re-use
>> if you weren't using BASIC - that was fundmentally my
> Maybe you can send your locations or even write up an article
> on your great work and publish it?

I've been thinking about that - pretty much a 16x16 color-coded
grid - one color for "can always use", another color for "can use
if BASIC is not needed", and certainly a color for "unproven".

I don't think I've ever seen such a chart, so I might as well make
the first version of it and get it into circulation for better refinement.

Naturally, there should be one chart per ROM/machine type for
best effect.  I'm qualified to work on ones for PET2001/BASIC 1.0,
PET2001/CBM30xx BASIC 2.0, CBM40xx/BASIC 4.0, CBM/80xx/BASIC 4.0,
VIC-20, and C-64/SX-64.  I'm not nearly as well versed on the C128, the CBM
B-Series, C16, etc., but if I can make a start on the machines I know,
someone else can take up the mantle for the other varieties.

>> It's been really exciting to make some progress on these
>> bugs after so long.  I started working on this project over
> Yes, it's really great work you're doing there!

If anyone wants to play with what I have, drop me a line.  I can shoot off
a small (few K-bytes) file that you would load, then run with a "real"
game disk mounted in drive 8.  I've tested things with half-a-dozen
disk images I have lying around, but at the moment, the only
real 8-bit hardware I have close by is bare motherboards (one of
my other projects is to get a stripped Static PET working, along
with a 4032 board).  I don't have any disks, but I do have a
C2N232 with me (and a couple of DIP AVRs so I could make a
dedicated C2N232 if I wanted to).

The version for the 8032 seems to be ready to unveil, and the
40-column version works and is playable except for some screen
garbage when the game scrolls the text.


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