Subject: Re(4): Port to 8xx embedded PPCs
To: Ignatios Souvatzis <>
From: Benjamin Herrenschmidt <>
List: tech-embed
Date: 06/20/2000 17:15:08
On Mon, Jun 19, 2000, Ignatios Souvatzis <> wrote:

>> Regarding the kernel, the MMU is different, so all the memory management
>> stuff need probably a complete rewrite.
>how different is it, exactly?

It has only TLBs, no hash table (a bit like the 603 but the TLBs and
exception mecanisms are different). It provides a different set of
special registers for use in those exceptions (TLB reload). The number of
TLBs can be different between processor models. That's all I know for
now, I didn't dive in the manual yet. But for example, linux/ppc uses
completely different exception handlers for TLB reloads than it uses for
604-like (hash table based) or 603-like (TLB only) CPUs.