From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-patches-return-76240-listarch-gdb-patches=sources.redhat.com@sourceware.org>
Received: (qmail 6603 invoked by alias); 31 Oct 2010 13:25:09 -0000
Received: (qmail 6555 invoked by uid 22791); 31 Oct 2010 13:25:06 -0000
X-SWARE-Spam-Status: No, hits=-1.4 required=5.0	tests=AWL,BAYES_05,TW_EG,T_RP_MATCHES_RCVD
X-Spam-Check-By: sourceware.org
Received: from sibelius.xs4all.nl (HELO glazunov.sibelius.xs4all.nl) (83.163.83.176)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sun, 31 Oct 2010 13:23:51 +0000
Received: from glazunov.sibelius.xs4all.nl (kettenis@localhost [127.0.0.1])	by glazunov.sibelius.xs4all.nl (8.14.3/8.14.3) with ESMTP id o9VDLA3B009661;	Sun, 31 Oct 2010 14:21:10 +0100 (CET)
Received: (from kettenis@localhost)	by glazunov.sibelius.xs4all.nl (8.14.3/8.14.3/Submit) id o9VDL6OT022353;	Sun, 31 Oct 2010 14:21:06 +0100 (CET)
Date: Sun, 31 Oct 2010 13:25:00 -0000
Message-Id: <201010311321.o9VDL6OT022353@glazunov.sibelius.xs4all.nl>
From: Mark Kettenis <mark.kettenis@xs4all.nl>
To: pedro@codesourcery.com
CC: gdb-patches@sourceware.org, hjl.tools@gmail.com
In-reply-to: <201010162149.36890.pedro@codesourcery.com> (message from Pedro	Alves on Sat, 16 Oct 2010 21:49:36 +0100)
Subject: Re: PATCH: gdbserver: Clear regcache if buf is NULL
References: <20100203174414.GA29948@lucon.org> <201010162100.47407.pedro@codesourcery.com> <AANLkTi=BEHZKetmGy10n0G_B4RvbEO53Bw5xDAiQN=0=@mail.gmail.com> <201010162149.36890.pedro@codesourcery.com>
Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <gdb-patches.sourceware.org>
List-Subscribe: <mailto:gdb-patches-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/gdb-patches/>
List-Post: <mailto:gdb-patches@sourceware.org>
List-Help: <mailto:gdb-patches-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: gdb-patches-owner@sourceware.org
X-SW-Source: 2010-10/txt/msg00405.txt.bz2

> From: Pedro Alves <pedro@codesourcery.com>
> Date: Sat, 16 Oct 2010 21:49:36 +0100
> 
> On Saturday 16 October 2010 21:16:37, H.J. Lu wrote:
> > >
> > > Thanks, and sorry as for not coming back to this promptly.
> > > Hmm, I don't think I have a way to trigger that.
> > > So is the registers' value really zero, or should gdb
> > > ideally present them as not available (and zero is just a
> > > hack)?
> > >
> > 
> > You will see it only on machines with XSAVE and enabled in OS.
> > Please see
> > 
> > 13.6 XSAVE/XRSTOR AND PROCESSOR EXTENDED STATE
> > MANAGEMENT
> > 
> > in
> > 
> > Intel® 64 and IA-32 Architectures Software Developer’s Manual
> > Volume 3A: System Programming Guide, Part 1
> > 
> > Basically values in vector registers may not be valid, depending
> > on vector state.
> 
> Okay, thanks.  The changes I'm working on would make gdb print
> for such registers:
> 
>  (gdb) info registers
>  ...
>  foo-register             *value not available*
>  ...
> 
> rather than:
> 
>  (gdb) info registers
>  ...
>  foo-register             0x0    0
>  ...
> 
> Trying to print the register's value will show something
> like "$1 = <unavailable>", and using it's value in expression
> evaluation to determine a computed expression value, an error
> will be reported.
> 
> Does that sound good?  Or do you think keep using 0 would
> be better in this case?

I think that sounds good.