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Re: Linux/MIPS for DECstations...

To: linux-mips@fnet.fr
Subject: Re: Linux/MIPS for DECstations...
From: paul@softway.com.au (Paul Antoine)
Date: Wed, 1 Oct 1997 08:53:14 +3400 (EST)
In-reply-to: <199709302112.OAA04252@dull.cobaltmicro.com> from "Ralf Baechle" at Sep 30, 97 02:12:04 pm
Organization: Softway Pty Ltd
Hi Gang,

Ralf wrote:

> Ok, bug #1:
> 
> 
> [...]
>         lw      k1, THREAD_PGDIR(k1)
>         sll     k0, k0, 2
>         addu    k1, k1, k0
>         mfc0    k0, CP0_CONTEXT
>         lw      k1, (k1)
>         srl     k0, k0, 1
>         and     k0, k0, 0xffc
>         addu    k1, k1, k0
>         lw      k0, (k1)
> [...]
> 
> Unlike the R4000 (64bit!) the R3000 context register refers to an
> array of four byte entries.  So you must delete the srl instruction.

...I should probably say that I think this code is of dubious
parentage!  It would probably be best for you to look closely at the
MMU code.  I was only just getting my head around the R3K MMU when I
ran out of time to keep working on it, so I'd suggest you might even
want to throw it away and write it again!

Once the MMU code is up I'm expecting that we'll then spend most of
our time on device driver code (which is a bit easier!), so if you're
able to help here, Ralf, we should be able to move forward a lot
faster.

Regards,
Paul
_______________________________________________________________________________
Paul M. Antoine,                                        Net: paul@sw.oz.au
Softway Pty Ltd                                         WWW: www.softway.com.au
PO Box 305, Strawberry Hills, NSW 2012, Australia       Tel: +61 2 9698 2322
Level 2, 79 Myrtle St, Chippendale, NSW 2008, Australia Fax: +61 2 9699 9174

"It is the lack of acceptance of diversity which threatens to 
 destroy society, NOT the free expression of it." - Me.

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