Subject: Re: emulating MMU on 68020?
To: Hubert Feyrer <hubert.feyrer@informatik.fh-regensburg.de>
From: Ignatios Souvatzis <is@beverly.kleinbus.org>
List: port-m68k
Date: 09/25/2000 19:39:06
On Mon, Sep 25, 2000 at 05:02:10AM +0200, Hubert Feyrer wrote:
> 
> I just read chapter 1.5.1, Virtual Memory, of the 68020 Manual (see
> http://ebus.motorola.com/brdata/PDFDB/MICROPROCESSORS/32_BIT/68K-COLDFIRE/M680X0/MC68020UM.pdf),
> and wonder if it would be possible to emulate a MMU (68851).
> Machines without one (e.g. the Cisco IGS) could benefit of that.
> 
> I understand that it would be slow, but would it be doable at all, or am I
> missing something important?

AFAICT without actually rereading the manuals, yes, it should work.

Unfortunately, it won't work for the Amiga machine with the pseudo-68EC030...
that one has enough MMU registers to look like a full one, but it fails some
MMU tests.

Regards,
	-is