> For the time being, how about introducing a predicate (function) to
> ppc-sysv-tdep.c (or perhaps rs6000-tdep.c) named
> have_floating_point_registers_p() (or something along those lines).
> 
> In the short term this could be defined as:
> 
> int
> have_floating_point_registers_p (struct gdbarch *gdbarch)
> {
>   const struct bfd_arch_info *arch_info = gdbarch_bfd_arch_info (gdbarch);
> 
>   /* Note: It has been proposed that a ``ppc_fp0_regnum'' member be added
>      to the ppc tdep struct.  If/when this occurs, it may be preferable to
>      implement this as:
> 
>        struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> 
>        return tdep->ppc_fp0_regnum >= 0;
>    */
> 
>   return arch_info->mach != bfd_mach_ppc_e500;
> }

I called it ppc_floating_point_unit_p().

> It occurs to me that such a predicate would be useful for checking
> the state of a global variable in the event that a command similar to
> ``set nomipsfpu'' were added for the powerpc.  (Well, maybe.  Then
> again, maybe it'd be better to just set ppc_fp0_regnum to -1 when
> such a setting were made.)

It is definitly better than a ppc_fp0_regnum test.  As with the MIPS, 
it's one thing to have FP registers, it is another to use them.

> In any event, a name like have_floating_point_registers_p() is
> reasonably self docuementing whereas ``tdep->ppc_fp0_regnum >= 0''
> requires a little bit more thought to discern the meaning.

How about the attached?

Andrew