[Coco] DECB -> Pi2/3

[Gene Heskett]

On Monday 06 March 2017 14:57:07 James Ross wrote:

> Hey Gene, thanks for the reply. I always enjoy reading your messages
> here on the list. You have a unique way expressing yourself in writing
> that is enjoyable to read.  I do try and stay up w/ list even though I
> don't post much on here, mainly on Facebook.
>
> Gene Heskett wrote:
> > ... <snip> ...
> > But those are the I/O choices on the pi's. USB, write your own GPIO
> > stuff, or build an fpga card that talks spi. The latter will give
> > you access to all the power of that quad core, 1.2 GHz clocked arm
> > A53 processor.
>
> I’d love to spend time learning the low-level I/O and other
> capabilities of the Pi …
>
> > And the ability to do most anything such as running nitros9
> > at a higher speed than it can run natively on the coco3 ...
>
> I’ve thought about this too.  Not sure this is exactly what you’re
> referring to, but it would be quite neat to see NitrOS9 ported to
> native ARM machine code on the Pi.  No 64k restriction – full address
> space / running at full speed using multiple cores … very, very lean. 
> Very quick boot. No Linux bloat. <- not that I am dissing Linux,
> however!!! :)
>
If its a direct assembly, those limits would still apply I think. I would 
be a bit leery of an assembler that took a 16 bit register and extended 
it to 32 bits without its calling a sub of some sort to actually check 
the validity of the added 16 bits.  That would be a bit like a 5 year 
old poking at a 6 foot Western Diamondback with a 2 foot stick.

Thats not to say that it can't be done, but it would take some carefull 
editing of both header files and the assembly code, trying to keep it 
from becoming one big flat memory mess.  That was the root cause of 90% 
of the crashing the amiga's did back in the day.  Processes scribbling 
on each others memory and it goes boom.
 
> > ...   And thats just the starting target. Much
> > like the original coco, your imagination is the limit of what you
> > can do. And do it at 20% of the original coco's $400 for a 4k memory
>
> Absolutely! And you’re not even taking into account inflation!

I hated to bring it up. I'm old enough to remember when a loaf of bread 
was 8 cents, and a pack of Lucky Strike cigs weren't much more. 13 cents 
IIRC. I think that makes me an old fart, now doesn't it?

> James


Cheers, Gene Heskett
-- 
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