Re: m68k structure return register

[Vladimir Prus <vladimir@codesourcery.com>]

On Wednesday 19 September 2007 17:31:36 Daniel Jacobowitz wrote:
> On Wed, Sep 19, 2007 at 12:24:27PM +0400, Vladimir Prus wrote:
> > > Group I -- monitor.mt -- just m68k-tdep.c
> > > 
> > >         1. m68k-*-aout*                                 a1
> > >         2. m68k-*-coff*                                 a1
> > >         3. m68k-*-elf*                                  a0
> > >         6. m68k-*-uclinuxoldabi*                        a0
> > >         7. m68k-*-uclinux*                              a1
> > >         9. m68k-*-rtems*                                a0
> > > 
> > > In gdb, all target here use the register set in m68k_gdbarch_init -- 
> > > currently A1, which register is wrong for half of targets. I'll get to this
> > > group shortly.
> 
> Which of these are ELF?  I know RTEMS is; I suspect both uclinuxoldabi
> and uclinux are.  You can differentiate based on ELF-ness in
> m68k_gdbarch_init.  Lots of other targets do that too.  Then you can
> set the default to a1 for non-ELF and a0 for ELF, and that will fix
> m68k-elf and m68k-rtems without breaking m68k-aout or m68k-coff.

Yeah, that's better.

> m68k-uclinux and m68k-uclinuxoldabi are harder.  Do you know how old
> m68k-uclinuxoldabi is, and whether we need to support it in GDB?

No.

> If not, you can treat it just like m68k-linux.  It is likely that
> the Linux OS/ABI sniffer will already accept uClinux binaries.

It does not seem so. The debuggable .gdb ELF binary does not have the
.note.ABI-tag section so the linux sniffer won't catch it. Is there
anything else I can check for?

- Volodya