Re: [Qemu-devel] qemu alpha?

[Rob Landley]

On Saturday 20 October 2007 3:56:12 am J. Mayer wrote:
> On Fri, 2007-10-19 at 19:49 -0500, Rob Landley wrote:
> > On Sunday 14 October 2007 5:14:27 am J. Mayer wrote:
> > > On Sun, 2007-10-14 at 11:19 +0200, Oliver Falk wrote:
> > > > Hi list!
> > >
> > > Hi you !
> > >
> > > > Just wanted to know how far the progress on alpha target is? I would
> > > > be happy if I have some 'virtual alpha' to test new isos.
> > > >
> > > > If I can help some way (I have a few alphas around). Let me know.
> > >
> > > I'm happy to see someone interresting in improving Alpha support, which
> > > is .... very alpha for now !
> >
> > I'm interested in testing Alpha too, but I haven't seem a
> > qemu-system-alpha show up yet.  Alas, I have no hardware or specific
> > expertise in this platform, I'm just trying to build and boot Linux
> > kernels (and corresponding root filesystems) on as many emulated target
> > platforms as I can.
>
> There are a lot of things missing for qemu-system-alpha to be available:
> - the PALCode emulation is far from being complete or even usable

I have no idea what that is.

> - there is no hardware machine emulation for Alpha in Qemu.
> As I have no Alpha platform, I don't know much about the hardware to be
> emulated.

I do know that the ev6 bus is the same as the Athlon used.

When Compaq bought the corpse of DEC back in the mid-90's, they weren't 
interested in their chip designers, so AMD scooped up most of the Alpha 
design team.  AMD then asked them "ok, if you guys were going to design an 
x86 compatible processor, what would it look like?"  The result was the 
Athlon back around 1997.  You could actually stick one in an Alpha 
motherboard, and the only reason it wouldn't boot is the bios was alpha 
machine language instead of x86 code.  Everything else was the same, because 
it's what the designers were familiar with.

So if you slap an Alpha in a virtual x86-64 PC motherboard, you're not too far 
off.

Here's one spec:
http://web.archive.org/web/19990913123756/http://www.unix-ag.org/Linux-Alpha/Architectures/LX164.html

Rob
-- 
"One of my most productive days was throwing away 1000 lines of code."
  - Ken Thompson.