Re: crosstool-0.27 demo-arm.sh fail

[Marius Groeger <mgroeger at sysgo dot com>]

On Fri, 27 Feb 2004, Daniel Kegel wrote:

> Marius Groeger wrote:
> >>>BTW Dan, have you tried the softfloat patched gcc on an ARM V4 system,
> >>>ie. _not_ XScale?
> >>
> >>No.  I've hardly tried it anywhere at all.  In fact, I haven't even
> >
> >
> > See my other posts on the matter. The patch in question makes GCC call
> > the AS with cpu=xscale. With good reason it seems, as the softfloat
> > routines don't compile with anything less. So I believe that patch is
> > only suitable for --with-cpu=xscale gcc's.
>
> Ah, so even for people not running with -msoft-float, the patch
> would cause trouble for non-xscale cpus?  If that's the
> case, we probably need a patch with a bit more finesse.

Yes. I tried to modify the patch to make armv4 the default arch for
AS, but then the code doesn't assemble (complains about "bx lr"
AFAIRC).

I've contemplated the problem a bit during the week end. We seem to
have to problems at hand here:

  1. compile options related to fp passed to the gcc and branded
     into the ELF objects (hard fp, soft fpa, soft vfp)

  2. true soft float routines, as provided by the patch

First we should address 1.), and similar to what other archs to. That
"only" requires compiling the stuff in libgcc.a twice, ie.
one time regularly and another time with -msoft-float. This compiler
would be completely ok for the majority of problems people run into,
that is: kernel routines or bootloaders compiled with -msoft-float and
referencing stuff in libgcc.a.

Then we can tackle 2.) which is a perfect play ground for the FP
hackers and performance hunters.

Obviously, the modifications should generic in terms of
the ARM architecture.

Any takers?

Unfortunately I'm working with gcc 3.2.3 and cannot easily (read: not
at all) switch to a higher gcc at this time.

Regards,
Marius

-- 
Marius Groeger <mgroeger@sysgo.com>
Project Manager

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