Re: pmap without RAM in the first 256MB segment

[Frank Wille <frank%phoenix.owl.de@localhost>]

On Tue, 16 Mar 2010 07:48:36 -0700
Matt Thomas <matt%3am-software.com@localhost> wrote:

> > The pmap_bootstrap() can only work when it finds RAM between
> > 0x00000000 and 0x10000000 (is this correct?). For the CyberstormPPC
> > I was lucky that the RAM base address of 0x08000000 is in this
> > area. But what can we do for computers without (useful) RAM in the
> > first segment (probably only Amigas are affected)?
> > 
> > Is it easy to fix/enhance pmap, or should I regard that a
> > show-stopper?
> 
> Since exceptions are delivered to address 0x0000-0x2fff, I not sure
> how it can even work unless they use the boot vectors at 0xfff00000
> (MSR[IP] = 1).

Yes, we are using "option PPC_HIGH_VEC" in amigappc, which I implemented
some time ago. This works fine.


> If that's true, then it's going to require
> significant work to get OEA working.

That's what I feared. :|
Probably not worth it?


-- 
Frank Wille