Subject: Re: NetBSD ported to MPC860 / MPC8260?
To: Ignatios Souvatzis <>
From: Randy Devol <>
List: tech-kern
Date: 01/10/2000 09:17:34
At 10:39 AM 1/10/00 +0100, Ignatios Souvatzis wrote:
>On Sat, Jan 08, 2000 at 02:10:50PM -0800, Randy Devol wrote:
> >
> > They are call Block Translation Tables, or BATs.  The 850/860 have a
> > minimal MMU implementation, with no hardware support for marking blocks 
> are
> > read or modified (except by causing an exception).
> >
> > The MPC8260 has a core identical to the 603 (or pretty darn close).  It 
> has
> > BATs and the same MMU as the 603.  Porting NetBSD to a platform using the
> > MPC8260 should be a piece of cake.
>The existing NetBSD/*ppc pmap modules make heavy use of the BAT registers
>to map the kernel address space 1:1 (because the translation is off during
>interupt servicing, anyway); you will need to rewrite that one for the
>BATless cpu version.

I know! :-(  I am working on a BATless 850 port.  The 8260 has BATs, along 
with all other features of the 603 MMU.  If I were starting over, I would 
definitely choose an 8260 over an 850, not so much for processor 
performance, but for the ease of "porting" NetBSD.

-=O=- Randy  F-24 Mk I #32, Joint Venture