[Coco] The Continuing Saga of My 6809 Computer

[William Astle]

On 12-08-31 09:41 AM, Bill Pierce wrote:
>
>   I tried (just for fun) to assemble a couple of the ROMs in RainbowIDE using CCASM and all I had to do was "INCLUDE" the related equates files at the top of the source for each ROM. There was an instance of errors related to any "leax   $-1,x" to "leax   $-9,x" instructions. I just removed the "$"s  and they assembled fine as these were 0-9 and therefore could be decimal or hex. The same in positive numbers did not error.
>   There seems to be no "special" as instructions used in a lot of assemblers such as "conditional" instructions ect. As I said, they assembled. I'm pretty sure they would assemble on a Coco using EDTASM if line numbers were added.
> Again, I do not know how close they are to the roms but that would be easy to check against my actual roms in my Coco.

Something you'll want to watch out for is the ",PC" indexed modes. There 
are a couple of those in the color basic rom and a big stack in the 
coco3 rom. To get a correct build, you'll need to replace ",PC" with 
",PCR" for some assemblers (lwasm for one). ",PC" is supposed to mean 
"constant offset from PC" while ",PCR" is supposed to mean "calculate 
the offset to the specified address and use that as the offset from PC". 
Some assemblers (including mamou) treat ",PC" as if it were ",PCR". I 
don't know what CCASM does in this case.

You won't get an assemble error in the ",PC" vs. ",PCR" case, but you 
will get a nonfunctional result.

I know there is no apparently useful purpose for ",PC", but that is what 
the "official" word is on the difference between the two notations.

You may also get slight variations in the case of "0,r" but those will 
not cause incorrect functioning nor will they change the size of the 
resulting binary. ("0,r" may be assembled to ",r" depending on the 
assembler.)


>
> Music from the Tandy/Radio Shack Color Computer 2 & 3
> https://sites.google.com/site/dabarnstudio/
> Bill Pierce
> ooogalapasooo at aol.com
>
>
>
>
> -----Original Message-----
> From: jdaggett <jdaggett at gate.net>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Fri, Aug 31, 2012 11:05 am
> Subject: Re: [Coco] The Continuing Saga of My 6809 Computer
>
>
> On 30 Aug 2012 at 22:51, Bill Pierce wrote:
>
>>
>> How close are the sources in the HDBDOS release? The text at the top say they
> were created using the sources from the unravelled series. I think the sources
> are at:
>> http://roms.coco.l-w.ca/
>>
>> Music from the Tandy/Radio Shack Color Computer 2 & 3
>> https://sites.google.com/site/dabarnstudio/
>> Bill Pierce
>> ooogalapasooo at aol.com
>>
>
>
> Remember the COCO3 ROM source file is for the Mamou asembler. Using it with
> another
> assemble may not assemble correctly.
>
> james
>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco
>
>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco
>