Re: PET 4032 rom dumps

From: Andy Grady <grada719_at_aol.com>
Date: Mon, 30 Dec 2019 18:26:48 +0000
Message-Id: <75C9897C-E9D9-491F-A8BA-A707813F029B_at_aol.com>
Frank

From what I can tell right now the code in 8-4032-9 rom appears to be a support package. 

For example, The  redirection of the interrupts goes to a routine that clears the last key press and then executes the IRQ as normal.... it’s not called by any code in the rom from what I can see (using cbmxfer )

The section that processes the call sys xxxx,xxx,xxx,xx evaluates the xxx’s and stores the results in various zero page locations..... and then ends with a RTS (return to whatever called it), but there is no where in the code that actually calls this routine.

It does process key presses and also outputs data to the screen but at present can’t follow its purpose ..... it would need much deeper analysis.

My hypothesis therefore is that it is a support rom and not a standard alone product such as command-o.

Regards
Andy

Sent from my iPad

> On 29 Dec 2019, at 17:23, Andy Grady <grada719_at_aol.com> wrote:
> 
> I have taken a look at the code in the 8-4032-9 rom dump and whilst it disassembles OK, I haven’t as yet figured out the logic. 
> 
> There is a section which when called (for eg from sys xxxxx,xx,xx,xx) that takes the line, looking for numbers separated by commas… The first sections of the code redirects the "system interrupts" and the next resets it. Will look further over time.
> 
> The 4K rom is definitely the Command-O rom. 
> 
> Andy
> 
> 
>> On 29 Dec 2019, at 17:00, Francesco Messineo <francesco.messineo_at_gmail.com> wrote:
>> 
>>> On Sun, Dec 29, 2019 at 4:58 PM Jim Brain <brain_at_jbrain.com> wrote:
>>> 
>>> On 12/29/2019 8:41 AM, Andy Grady wrote:
>>>> Frank
>>>> 
>>>> Both ROMS are installed on $9000 socket
>>>> 
>>>> The 4K ROM looks identical to the Command-O ROM. Initialise SYS 36864
>>>> (I believe)
>>>> 
>>>> http://www.geocities.ws/davegostelow/PETroms/CmdOAd.jpg
>>>> 
>>>> Not sure about the other one right now.
>>>> 
>>>> Andy
>>> 
>>> Any chance you can dump and send to zimmers?
>> 
>> I attached the dumps to my first post in the thread. Once we know what
>> the dumps are, we can send the to zimmers if they aren't yet there.
>>> 
>>> 
>>> 
>> 
> 
Received on 2020-05-30 00:01:52

Archive generated by hypermail 2.3.0.