Re: [hatari-devel] MMU support

[Andreas Grabher <andreas.grabher@xxxxxxxxxxxx>]

There is some news on this:

Toni Wilen, who is working on WinUAE has added our MMU and made some additions to it, including correct exception handling for 68030 and also handling the SSW.
He told that he was able too boot AMIX (Amiga Unix). So the 68030 MMU should now be good enough to boot real MMU using systems!
The problem is, that the actual WinUAE CPU differs quite a lot from our Hatari-based one. So for me it is very hard to understand and implement all the necessary changes into Previous.

Maybe someone used to WinUAE>Hatari CPU differences can take a look?

Andreas


Am 21.01.2013 um 23:51 schrieb Eero Tamminen:

> Hi,
> 
> On sunnuntai 25 marraskuu 2012, Andreas Grabher wrote:
>> I think the 68030 MMU emulation of Previous used in Hatari is the first
>> full emulation of the 68030's MMU. Like Thomas said, it is still in
>> experimental state, because there has only been little testing. Recently
>> some bugs have been discovered and fixed. Hopefully there are no more
>> bugs in the code. But one thing is still missing, although not just MMU
>> related: correct handling of the 68030's Special Status Word (SSW). It
>> is needed for the exception stack frame for bus and address errors. It
>> needs to be set on all (not just MMU) bus error and page fault
>> exceptions.
>> 
>> I do not yet understand all of the bits inside this SSW. I'd be happy if
>> anyone could explain them to me. I'll try to implement it, as soon as i
>> can understand it. The bits are explained in the MC68030UM.pdf (68030
>> users manual), page 295 (pt. 8.2.1).
> 
> Did I understand correctly that currently there's *no* SSW support and
> in practice this means that no real MMU using OS would work, as SSW
> is needed for recovering from the MMU exceptions?
> 
> The reason I ask is that I've mailed with couple of people who might
> be interested in trying NetBSD and Linux in Hatari.
> 
> 
> 	- Eero
> 
>