[Coco] 16/32 bit 6809 derivative

[Joel Rees]

2017/09/23 14:18 "Kip Koon" <computerdoc at sc.rr.com>:
>
> Hi Joel,
> You took the thoughts right out of my mind!  I have been wanting
something like that for years!  Would you be that guy who created the next
generation of 6809 MPUs?
>

Only if I could get someone to pay me.

Conceptually, it's not that hard. Sign extend everything.

Memory management will take a bit of thought, of course. The gadgetry in
the Coco3 wouldn't be very useful.

Ultimately, we would prefer assembly-language compatibility, but then
everyone thinks 68K or ARM.

But I like the 6809's simple instruction set.

> Kip Koon
> computerdoc at sc.rr.com
> http://www.cocopedia.com/wiki/index.php/User:Computerdoc
>
> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Joel Rees
> Sent: Friday, September 22, 2017 11:54 PM
> To: CoCoList for Color Computer Enthusiasts
> Subject: [Coco] 16/32 bit 6809 derivative
>
> A number of people are designing MMUs for their softcore Cocos.
>
> I'm wondering if I'm the only one who thinks about designing a CPU that
implements the 6809 instruction set in 16-bit accumulators and 32-bit index
registers, with a 16-bit instruction set accessed by pre-bytes.
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco
>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco