Re: [Qemu-devel] [PATCH 1/16] ARM Add ARM 920T identifiers

[Jamie Lokier <jamie@shareable.org>]

Laurent Desnogues wrote:
> On Tue, May 26, 2009 at 11:56 AM, Jamie Lokier <jamie@shareable.org> wrote:
> > Laurent Desnogues wrote:
> >> On Tue, May 26, 2009 at 11:39 AM, Vincent Sanders <vince@kyllikki.org> wrote:
> >> > I will post the updated patch to the list shortly. Please be assured
> >> > that every program we have tried (boot loaders, Linux, BSD etc.)
> >> > appears to function as expected, to the point it had not been
> >> > apparient the 920 was a different ISA version to the default emulation.
> >> >
> >> > So while this is indeed a technical issue, in practice it doesnt seem
> >> > to be a major problem.
> >>
> >> It could be a major problem if you start playing with ARM/Thumb
> >> interworking.
> >
> > I'm curious.  How would code built for ARMv4T interworking fail on an
> > ARMv5T emulator?
> 
> It shouldn't.  I was thinking about how most people are misusing their
> toolchain and think that if QEMU runs correctly some code, it should
> run on the target.  In that particular case, that will fail :-)  For instance
> LDM with PC used as procedure return does not behave the same
> in v4T and v5 IIRC.

I agree.  Especially for testing toolchains and architecture-specific
code, it would be quite nice :-)

I gather the x86 target is similarly lax with checking some things
that a real x86 checks.

-- Jamie