Subject: Re: NetBSD ported to MPC860 / MPC8260?
To: Randy Devol <firstname.lastname@example.org>
From: Ignatios Souvatzis <email@example.com>
Date: 01/10/2000 10:39:27
On Sat, Jan 08, 2000 at 02:10:50PM -0800, Randy Devol wrote:
> >Being targeted at the embedded world, however, they don't have hardware
> >floating point or the large-block memory mapper (I forget what this is
> >called, exactly). They do, however, have some cache and the small-block (4k
> >byte) MMU with a TLB.
> 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.
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