[Coco] Modifying Level1/coco1 for 6309 native mode
Bill Nobel
b_nobel at hotmail.com
Fri Feb 14 20:31:07 EST 2014
Yep, it is exactly as I thought. The entry point of L0604 is the setstat for SS.RsBit. I did a quick comparison on the documented level 2 RBF and level 1 RBF I had (very close to each other). ‘A' will contain LSB of X from register stack.
Although it’s like you said Robert depending on where you are in decoding it, U could contain different things. I found in rbf that U will usually have either a Path descriptor or Register pointers (sometimes pointer to buffer within path descriptor).
Side note - My god I still remember that??? (it’s been 20+ years)
-Bill
On Feb 14, 2014, at 5:37 PM, Bill Nobel <b_nobel at hotmail.com> wrote:
> Thanks for the comment Robert, much appreciated.
>
> I still have the code Curt and I did, I will dig up RBF.asm and see if you are correct on that offset and what U is pointing to at the time. U should be pointing to the register stack if I remember correctly. I have it on my server just a matter of where, 6TB to dig through. I am pretty sure though that U is pointing to Register stack.
>
> -Bill
>
> On Feb 14, 2014, at 5:07 PM, L. Curtis Boyle <curtisboyle at sasktel.net> wrote:
>
>> Yeah, I wish I still had time to work on it (but I don't seem to even have time to update the games webpage these days). And there were some many things that Bill and I were looking at adding, too...
>>
>> L. Curtis Boyle
>> curtisboyle at sasktel.net
>>
>>
>>
>> On Feb 14, 2014, at 4:43 PM, Robert Gault <robert.gault at att.net> wrote:
>>
>>> Bill Nobel wrote:
>>>> You are on the right path Robert, When Curt and I started the project I had to reverse engineer everything. The defs files I modified for the 6309 register layout and other things we added. I encased them into ifdef, else etc for the reassembly. I basically added the Def reference to the code and reassembled it to make sure the module CRC was the same as the original. Once that was done I concentrated on the conversion to 6309.
>>>>
>>>> It was a process to get the boot files converted. The hardest was the initial REL, BOOT and OS9P1 to convert to 6309 and make it fit in the boot track
>>>>
>>>> -Bill
>>>>
>>>> On Feb 14, 2014, at 10:54 AM, L. Curtis Boyle <curtisboyle at sasktel.net> wrote:
>>>>
>>>>> This is exactly what Bill and I did to make NitrOS9 in the first place. :-)
>>>>> (To be honest, this earliest stage was much more Bill than me).
>>>>>
>>>>> L. Curtis Boyle
>>>>> curtisboyle at sasktel.net
>>>
>>> Bill and Curtis,
>>>
>>> Nice to hear from you guys! The original NitrOS-9 was an incredible piece of work given it was a two man operation.
>>>
>>> I think I may be wrong about one change in rbf.asm. I suggested
>>> shortly after L0604
>>> lda R$X+1,u was $05,u
>>>
>>> but the above may not be a register stack. The only way to tell will be to see if the code runs for both 6809 and 6309 systems.
>>>
>>> Robert
>>>
>>>
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>>>
>>
>>
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