Start address of unknown ROMs and cartridges

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Start address of unknown ROMs and cartridges

Baltissen, GJPAA (Ruud)
Hallo allemaal,


Mike wrote:
> I disassembled SUPER*TOOL just enough to get it to run.  It starts with "SYS 37000"

Some weeks ago I started to clear various drawer, cupboards etc. I ran into quite some unmarked cartridges for the C64/128. I just put them into a C64 and looked what happened. Those that didn't start automatically I tried to start with SYS32768. Sometimes that worked, sometimes it didn't (maybe they did something but I didn't see anything). Quite lot of those 'not working' cartridges had soldered ROMs which would mean quite some time compared to the gain IMHO so I gave away to a member of our club who was willing to have a further look at them.

When testing all those cartridges I gave my thoughts about those not-starting ones. Two thoughts were:
- Why not auto starting? I can imagine that ROMs have to be started only after the C64 has started up completely.
- In that case, why not SYS32768?
- If not 32768, how to find out the starting address?

So, Mike, how did you find out that it was 37000? If you look at the BIN and see that the first bytes are a copyright text, It is obvious to start with the code behind that text. But 37000? I just hope there is a trick involved we all can learn from.


> but requires BASIC 2 (won't work on BASIC 4).

I assume you found this out by putting the ROM in a 8032 as well?


Met vriendelijke groet / With kind regards,
Ruud Baltissen

www.Baltissen.org



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Re: Start address of unknown ROMs and cartridges

traymond
I have seen this even on Vic-20 cartridges you have to know the starting address
was this perhaps before many companies didnt know about self starting I guess Rom's?

I have run into this with Cartridge Rom Snapshots of Cartridges.
These are I think memory dumps so maybe this happened with C64 cartridges too
so once upon a time there were instructions with the cartridge on how to start the Rom program.

Hey with Vic 20 Rom dumps of utilities and games these you 
LOAD"GAME",8,1   then SYS64802 to start.
Some games etc the screen is either too far to the left or right is there a POKE or PEEK to 
straighten out the screen like in the loading routine?

Terry Raymond

On Tuesday, November 1, 2016, Baltissen, GJPAA (Ruud) <[hidden email]> wrote:
Hallo allemaal,


Mike wrote:
> I disassembled SUPER*TOOL just enough to get it to run.  It starts with "SYS 37000"

Some weeks ago I started to clear various drawer, cupboards etc. I ran into quite some unmarked cartridges for the C64/128. I just put them into a C64 and looked what happened. Those that didn't start automatically I tried to start with SYS32768. Sometimes that worked, sometimes it didn't (maybe they did something but I didn't see anything). Quite lot of those 'not working' cartridges had soldered ROMs which would mean quite some time compared to the gain IMHO so I gave away to a member of our club who was willing to have a further look at them.

When testing all those cartridges I gave my thoughts about those not-starting ones. Two thoughts were:
- Why not auto starting? I can imagine that ROMs have to be started only after the C64 has started up completely.
- In that case, why not SYS32768?
- If not 32768, how to find out the starting address?

So, Mike, how did you find out that it was 37000? If you look at the BIN and see that the first bytes are a copyright text, It is obvious to start with the code behind that text. But 37000? I just hope there is a trick involved we all can learn from.


> but requires BASIC 2 (won't work on BASIC 4).

I assume you found this out by putting the ROM in a 8032 as well?


Met vriendelijke groet / With kind regards,
Ruud Baltissen

www.Baltissen.org



De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de
geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te
nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit
e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken.
Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige
overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij
overgebrachte virussen.

APG Groep N.V. is gevestigd te Heerlen en is ingeschreven in het
handelsregister van de Kamer van Koophandel Limburg onder nummer 14099617


The information contained in this e-mail is confidential and may be privileged.
It may be read, copied and used only by the intended recipient.
If you have received it in error, please contact the sender immediately by
return e-mail; please delete in this case the e-mail and do not disclose its
contents to any person. We don't accept liability for any errors, omissions,
delays of receipt or viruses in the contents of this message which arise as a
result of e-mail transmission.

APG Groep N.V. is registered in the trade register of the Chamber
of Commerce Limburg, The Netherlands, registration number: 14099617
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Re: Start address of unknown ROMs and cartridges

Gerrit Heitsch
On 11/01/2016 04:43 PM, Terry Raymond wrote:

> Hey with Vic 20 Rom dumps of utilities and games these you
> LOAD"GAME",8,1   then SYS64802 to start.
> Some games etc the screen is either too far to the left or right is
> there a POKE or PEEK to
> straighten out the screen like in the loading routine?

Usually that's done using the Cursor keys one the game is running. At
least with the Cartridges I know.

  Gerrit



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Re: Start address of unknown ROMs and cartridges

traymond
Hmmm okay interesting.
Thanks Gerrit

On Tuesday, November 1, 2016, Gerrit Heitsch <[hidden email]> wrote:
On 11/01/2016 04:43 PM, Terry Raymond wrote:

Hey with Vic 20 Rom dumps of utilities and games these you
LOAD"GAME",8,1   then SYS64802 to start.
Some games etc the screen is either too far to the left or right is
there a POKE or PEEK to
straighten out the screen like in the loading routine?

Usually that's done using the Cursor keys one the game is running. At least with the Cartridges I know.

 Gerrit



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Re: Start address of unknown ROMs and cartridges

Francesco Messineo
In reply to this post by Baltissen, GJPAA (Ruud)
On Tue, Nov 1, 2016 at 7:55 AM, Baltissen, GJPAA (Ruud)
<[hidden email]> wrote:
> Hallo allemaal,
>

> - In that case, why not SYS32768?
> - If not 32768, how to find out the starting address?

in the case of the Pet ROM in UD3, I guess sys 37000 is easier to
remember than sys 36864.
(Well, unless you are an asm programmer).
Frank

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Re: Start address of unknown ROMs and cartridges

Mike Naberezny
In reply to this post by Baltissen, GJPAA (Ruud)
On 10/31/16 11:55 PM, Baltissen, GJPAA (Ruud) wrote:
> So, Mike, how did you find out that it was 37000? If you look at the BIN
> and see that the first bytes are a copyright text, It is obvious to start
> with the code behind that text. But 37000? I just hope there is a trick
> involved we all can learn from.

I disassembled the ROM using da65.  Its output includes labels for locations
accessed by the code.  I looked for familiar addresses.  There was a label for
$70, which is the CHRGET routine in RAM.  BASIC wedges patch this routine, so
I knew the ROM was some kind of wedge.

I looked for where the ROM writes to $70+ to install its CHRGET patch.  I
found it at $9088 and below it at $9094 was the code to print the banner.
$9088 makes the nice decimal number in SYS 37000 so I figured that was it.
The MONJANA/1 ROM uses a similarly nice number; it starts with SYS 38000.

>> but requires BASIC 2 (won't work on BASIC 4).
>
> I assume you found this out by putting the ROM in a 8032 as well?

I tried SYS 37000 on a 2001 with BASIC 2 and it worked.  I then tried it on an
8032 and it crashed.  Since the 8032 has BASIC 4, I thought it might be a
difference between BASIC 2 and 4.  I went back to the disassembly and looked
for calls into the BASIC ROM area.  I looked up a few of them in "Programming
the PET/CBM" by Raeto West.  That book has a map of BASIC routines and their
addresses in BASIC 1, 2, and 4.  One of the calls was to $C9E2, which only
works on BASIC 2.

Regards,
Mike

--
Mike Naberezny ([hidden email]) http://6502.org

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