From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22236 invoked by alias); 7 Mar 2010 19:49:21 -0000 Received: (qmail 22228 invoked by uid 22791); 7 Mar 2010 19:49:20 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00 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, 07 Mar 2010 19:49:16 +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 o27JkaA9014056; Sun, 7 Mar 2010 20:46:36 +0100 (CET) Received: (from kettenis@localhost) by glazunov.sibelius.xs4all.nl (8.14.3/8.14.3/Submit) id o27JkYU7030157; Sun, 7 Mar 2010 20:46:34 +0100 (CET) Date: Sun, 07 Mar 2010 19:49:00 -0000 Message-Id: <201003071946.o27JkYU7030157@glazunov.sibelius.xs4all.nl> From: Mark Kettenis To: froydnj@codesourcery.com CC: hjl.tools@gmail.com, mark.kettenis@xs4all.nl, gdb-patches@sourceware.org In-reply-to: <20100307190959.GY16726@codesourcery.com> (message from Nathan Froyd on Sun, 7 Mar 2010 11:09:59 -0800) Subject: Re: PATCH: 0/6 [2nd try]: Add AVX support References: <20100304180219.GA10826@intel.com> <20100306221634.GA21133@intel.com> <201003071416.o27EGPfu007140@glazunov.sibelius.xs4all.nl> <6dc9ffc81003070637q3e554ba4n2ee6053c2fd24511@mail.gmail.com> <6dc9ffc81003070831yf923b9bj83da56cb9c83a751@mail.gmail.com> <6dc9ffc81003070840x649dcc23qa088fddd69df7e54@mail.gmail.com> <20100307190959.GY16726@codesourcery.com> Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2010-03/txt/msg00279.txt.bz2 > Date: Sun, 7 Mar 2010 11:09:59 -0800 > From: Nathan Froyd > > On Sun, Mar 07, 2010 at 08:40:10AM -0800, H.J. Lu wrote: > > My first approach works here since XMM and YMM register have the same > > register numbers. We can solve it with 2 alternatives: > > > > 1. Give a different DWARF register number for YMM register, > > which is an incompatible ABI change. > > 2. Implement YMM registers as a super set of XMM registers, which > > is my first approach. > > The third alternative--again, what's adopted for the PPC SPE 64-bit > registers--is to give %ymmNh their own DWARF register numbers. I > suppose it's also ABI-incompatible, but it seems like it fits with your > approach much better than either of the above alternatives. I don't think that would be a good idea. It means you can't refer to something stored in a %ymmN register with a single register number. The compiler will have to use a more complicated expression (which may not be possible for older debug info formats) for these. As a result, things like "info address" become rather useless.