Re: [RFA] ppc/rs6000: use gdbarch_ps_regnum

[Andrew Cagney <cagney at gnu dot org>]

Michael Snyder wrote:
> > On Fri, 15 Oct 2004 17:41:10 -0700
> > Michael Snyder <msnyder@redhat.com> wrote:
> >
> > > I just happened to notice this.  Gdbarch implements PS_REGNUM,
> > > so there's no reason to keep it privately in the tdep struct.
> >
> >
> > Is there some good reason to move it out of the private tdep
> > struct and into the public eye?
> >
> > I'll note that ppc_fp0_regnum is also in the tdep struct, and
> > something comparable (FP0_REGNUM) is also in the gdbarch name space.
> > Yet, rs6000-tdep does not set FP0_REGNUM via set_gdbarch_fp0_regnum()
> > and I happen to like it this way.  The reason is that there's no good
> > reason (that I know of) for the other parts of GDB to be aware of this
> > register numbering.  Also, putting the indexes into the tdep struct
> > gives a uniform mechanism of accessing (most of) the PPC related
> > register numbers.  If we were to move either the PS or FP0 register
> > number back out to gdbarch, then we'd be accessing some of the
> > registers via one mechanism and these others via another.
> > (Unfortunately, we still have SP_REGNUM and PC_REGNUM in gdbarch land.
> > But there are good reasons for other, non-ppc specific portions to
> > know about these register numbers.)

Kevin's correct, and just like DEPRECATED_FP_REGNUM, SP_REGNUM, 
PC_REGNUM, and FP0_REGNUM are all on my hit list :-)

Andrew

> No special reason -- I just figured that if there was a public interface,
> there might be some motivation to use that instead of a private interface.
>
> PS_REGNUM is referred to quite a lot -- but mostly in other tdep and nat
> files that are orthogonal to this one.  The major exception being 
> std-regs.c,
> which sort-of groups PS in there with PC, SP and (cover your ears, Andrew)
> FP.
>
> I have no attachment to it, though, if you prefer it the way it is.