Re: [RFA] W.I.P. AltiVec ppc registers support.

[Daniel Jacobowitz <drow@mvista.com>]

On Sun, Dec 02, 2001 at 01:34:16PM -0500, Elena Zannoni wrote:
> Hold on, I looked at the altivec.org and at the linuxppc.org mailing
> lists.
> 
> There is actually a patch posted at the beginning of September to
> which you replied at some stage.  And this patch is similar to the one
> I have used for implementing GDB altivec support.

OK, my memory failed me; I remembered someone describing it but not
that they had posted a patch.  Sorry.

> The version of the patch I have was provided by Motorola, and they are
> about to submit it publicly. The patch is virtually identical to the
> one posted on linuxppc.org except for the definition of PT_VR0 which
> in the latter is (errouneously) made to be aligned on 128-bits.  So
> for the patch I have PT_VR0 is simply PT_FPSCR + 1, not 128.
> 
> My gdb implementation works also for machines w/o altivec ptrace
> support, because in that case the ptrace call just errors out and that
> condition is detected (I am talking about my original patch, w/o the
> changes that Kevin suggested). This was one objection to the kernel
> patch that I've seen raised on the linuxppc list.

Franz' comments completely account for mine in his reply:
  http://lists.linuxppc.org/linuxppc-dev/200109/msg00045.html

No one ever answered him publicly, AFAIK.  He also told me privately
that he could not contribute code easily because of his relationship
with Caltech.

If Motorola's patch is accepted, I've no objection to this going in
as-is.  If Paul chooses to hold out for a different interface, of
course, I'd rather it didn't.

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer