From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16947 invoked by alias); 22 Mar 2011 06:11:34 -0000 Received: (qmail 16889 invoked by uid 22791); 22 Mar 2011 06:11:32 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW X-Spam-Check-By: sourceware.org Received: from mail-iy0-f175.google.com (HELO mail-iy0-f175.google.com) (209.85.210.175) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 22 Mar 2011 06:11:26 +0000 Received: by iyb26 with SMTP id 26so8846623iyb.20 for ; Mon, 21 Mar 2011 23:11:25 -0700 (PDT) MIME-Version: 1.0 Received: by 10.43.57.78 with SMTP id wf14mr8546750icb.138.1300774285127; Mon, 21 Mar 2011 23:11:25 -0700 (PDT) Received: by 10.42.72.196 with HTTP; Mon, 21 Mar 2011 23:11:25 -0700 (PDT) In-Reply-To: References: Date: Tue, 22 Mar 2011 06:11:00 -0000 Message-ID: Subject: Re: Clarification on PowerPC64 Linux ABI From: Andrew Pinski To: Rohit Arul Raj Cc: gcc Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org X-SW-Source: 2011-03/txt/msg00318.txt.bz2 On Mon, Mar 21, 2011 at 10:50 PM, Rohit Arul Raj wrote: > Hello All, > > I have a question regarding PowerPC64 bit ABI. Since GCC generates FP > instructions for Non FP code, i was running in to issues with > applications having interrupts (i have seen some threads with people > complaining about this). What kind of interrupts? Because FP code should only produce an interrupt at the first usage and that is it. Since all PowerPC64 machines have a FPU, there will be no emulation needed. The only other kind of interrupt I can think of is an unaligned load/store for a FPU load/store. If that happens then you have issues dealing with unaligned memory which is most like caused by undefined code. Most PPC64 machines are able to handle word aligned float/double load/stores without an unaligned exception happening. The reason why it is undefined because of alignment requirements in the C/C++ standard. I think you need to do some debugging to figure out why you get the unaligned exceptions. It is most likely a bug in your code. Thanks. Andrew Pinski PS -msoft-float does not work as we don't multilib on -msoft-float for PPC64.