From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30225 invoked by alias); 23 Feb 2008 15:40:54 -0000 Received: (qmail 30205 invoked by uid 22791); 23 Feb 2008 15:40:53 -0000 X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (66.187.233.31) by sourceware.org (qpsmtpd/0.31) with ESMTP; Sat, 23 Feb 2008 15:40:36 +0000 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id m1NFeXfx014404; Sat, 23 Feb 2008 10:40:33 -0500 Received: from zebedee.pink (vpn-14-6.rdu.redhat.com [10.11.14.6]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m1NFeWWG029494; Sat, 23 Feb 2008 10:40:32 -0500 Message-ID: <47C03E6F.5020005@redhat.com> Date: Sat, 23 Feb 2008 18:23:00 -0000 From: Andrew Haley User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Bob Plantz CC: gcc-help Subject: Re: C main 32/64 bit prologues differ References: <1203710407.6360.20.camel@localhost> In-Reply-To: <1203710407.6360.20.camel@localhost> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact gcc-help-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-help-owner@gcc.gnu.org X-SW-Source: 2008-02/txt/msg00285.txt.bz2 Bob Plantz wrote: > The prologues for the main function in C differ (at the assembly > language level) depending on whether it is compiled for 32-bit or 64-bit > in the x86 architecture. > > Also, adding a dwarf2 unwind table is the default in 64-bit mode, but > not in 32-bit. > > Can anyone point me to discussions about why it's done this way? The DWARF question I can answer: it's required by the processor- specific ABI. Andrew.