[Coco] The Hobbit ported to 6809 (Dragon64 and coCo2 64k)

Gene Heskett gheskett at shentel.net
Sun Aug 21 22:15:41 EDT 2016

On Sunday 21 August 2016 21:11:37 Barry Nelson wrote:

> Does anyone know a way of telling a CoCo 2 from a CoCo 1?
One possibility might be in the first few bytes of the basic rom at 
$A000. I had an old grey ghost first, (still have 2 or 3) and I fixed 
Jake Commanders little editor to live in high ram so it din't borrow a 
kilobyte of basic's memory.

But when I got my first coco2, it didn't run very well, lots of lag.  It 
seems that they had moved the keyboard scan routine a few bytes, and 
Jakes code was skipping the vector lookup in the first few bytes of the 
rom and was still jumping to the original address.  So I looked up the 
vector address and changed jakes code to use the vector address by 
getting it from the rom.  After that it worked great on either a coco or 
a coco2. So someplace in the first 32 bytes of the basic rom, there is a 
different vector integer for the keyboard polling routine.

But I'll defer to Art as to whether or not this is a good indicator of a 
coco1 or a coco2. Since most if not all the white/cream coco2's shiped 
with basic-1.1 it might work quite well.

That vectors address is mentioned in the basic book they came with IIRC.

Strange, the things I can remember from 30 years ago, but I'd have to 
hobble to the basement and find one of those books before I could quote 
it here.  Bad knee, worse back, I'm wearing out. Lots of miles on this 
soon to be 82 yo carcass.

Stay well & take care everybody.

> > Pere psergm at gmail.com
> > Sun Aug 21 18:54:38 EDT 2016
> >
> > Hi Brett,
> > thanks a lot for that pointer.
> > I have found that $FFFF contains $1B on a CoCo3, $B4 for a
> > Dragon/Tano and $27 on a CoCo2
> > Probably this could be a good 'signature' to look for ...
> > I will try to add the changes proposed by Art and this one tomorrow
> > I'd love to have a single binary working on the Tano/Dragon64, CoCo2
> > and CoCo3
> > despite the RAM constraints that suffers this project.
> >
> > cheers
> > pere

Cheers, Gene Heskett
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 soap, ballot, jury, and ammo. Please use in that order."
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Genes Web page <http://geneslinuxbox.net:6309/gene>

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