Re: Second Opinion on unknown PET option roms

From: Hans Liss <Hans_at_Liss.pp.se>
Date: Tue, 7 Sep 2021 17:32:39 +0200
Message-ID: <ac51f194-9052-05bb-6f55-64e5ff8a4d5e_at_Liss.pp.se>
I padded 901447_30_2001diag_0000.bin out with a 2k block and loaded it 
in VICE at $9000, so that the ROM ended up at $9800, and then ran "sys 
38912". This happened:

PET

So, clearly it's the Diagnostic Clip 901447-30 for PET 2001.

/Hans


On 2021-09-06 22:35, Hans Liss wrote:
>
> I used the VICE monitor to load that block into PET video RAM:
>
> diagnostic 320350g
>
> a8-a11 bad
>
> tv ram ok
>
> i-ram bad
>
> z-page ok
>
> a8-adr bad
>
> stack ok
>
> remove clip
>
> /Hans
>
> On 2021-09-06 22:14, Hans Liss wrote:
>>
>> 901447-30_2001diag_0000.bin seems to disassemble nicely at $9800, and 
>> http://mhv.bplaced.net/cbmroms/cbmroms.php lists "901447-30" as a 
>> "Diagnostic Clip" for PET 2001, to be located at 9800-9FFF. 
>> Incidentally, the code around $9979 seems to load bytes from $99ce to 
>> $99d8 to screen memory, so maybe someone more patient than I can 
>> figure out what it says? I suspect the entire block between $9985 and 
>> $99d8 is screen text, actually.
>>
>> 901484-03-2031ro_c000.bin seems to match "901484-03" on the same 
>> page, which describes it as DOS 2.6 Low for the 2031 drive, to load 
>> at c000. There's a copy of that ROM on 
>> http://www.zimmers.net/anonftp/pub/cbm/firmware/drives/old/2031/index.html, 
>> however, which seems to have nothing in common with this one. So 
>> that's strange.
>>
>> /Hans
>>
>> On 2021-09-06 21:39, Hans Liss wrote:
>>>
>>> Better link: 
>>> http://www.zimmers.net/anonftp/pub/cbm/firmware/misc/unknown/
>>>
>>> The low count of "a9" bytes in several of these is a sure sign it's 
>>> not 6502 code. I took a quick look at a few:
>>>
>>>   * 8in-cpm-trbdos.bin is definitely Z80 code (or 8085, perhaps?). A
>>>     CPM "driver" for 8-inch floppies, perhaps?
>>>   * 740turbo1-1.bin is also Z80 code.
>>>   * I suspect ultima-ii-v1-73.bin is also Z80 code.
>>>   * create-new-base.bin and 40-80-60h.bin seem to be something else,
>>>     like not program code at all.
>>>
>>> I found a fairly useful disassembler at 
>>> https://onlinedisassembler.com/odaweb/, by the way. I tend to use 
>>> wfdis for 6502 code, but this one has many other architectures and 
>>> accepts small hex dumps as input.
>>>
>>> /Hans
>>>
>>> On 2021-09-06 19:23, Bo Zimmerman wrote:
>>>> Hello all,
>>>>
>>>> Dave McMurtrie contributed a nice pile of PET option rom images to 
>>>> the funet/zimmers archive _at_ 
>>>> http://www.zimmers.net/.../computers/pet/other/index.html
>>>>
>>>> I had no trouble identifying and classifying most of them. However, 
>>>> there were several that I could either not get working, properly 
>>>> disassembled,, or just couldn't identify. This is fairly new to me, 
>>>> so I created a special place for them here:
>>>> http://www.zimmers.net/ano.../pub/cbm/firmware/misc/unknown/
>>>>
>>>> If anyone out there enjoys digital archeology, I'd ask you to give 
>>>> a second or third opinion on some of those unknown roms. It's 
>>>> possible the eproms were just corrupt or unreadable, but I'd sure 
>>>> like someone else to concur before I throw any of the images out.
>>>>
>>>> - Bo Zimmerman
>>>>
>>>>
Received on 2021-09-07 18:00:04

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