From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24841 invoked by alias); 26 Jan 2008 18:18:45 -0000 Received: (qmail 24827 invoked by uid 22791); 26 Jan 2008 18:18:44 -0000 X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (65.74.133.4) by sourceware.org (qpsmtpd/0.31) with ESMTP; Sat, 26 Jan 2008 18:18:20 +0000 Received: (qmail 17137 invoked from network); 26 Jan 2008 18:18:18 -0000 Received: from unknown (HELO digraph.polyomino.org.uk) (joseph@127.0.0.2) by mail.codesourcery.com with ESMTPA; 26 Jan 2008 18:18:18 -0000 Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.68) (envelope-from ) id 1JIpbd-0003up-86; Sat, 26 Jan 2008 18:18:17 +0000 Date: Sat, 26 Jan 2008 19:08:00 -0000 From: "Joseph S. Myers" To: Mark Kettenis cc: bauerman@br.ibm.com, luisgpm@linux.vnet.ibm.com, drow@false.org, brobecker@adacore.com, gdb-patches@sourceware.org Subject: Re: [RFC] Linux-specific ppc32 ABI In-Reply-To: <200801261535.m0QFZddH026156@brahms.sibelius.xs4all.nl> Message-ID: References: <1199991624.3343.19.camel@gargoyle> <20080111060629.GC12954@adacore.com> <1200066920.26270.9.camel@gargoyle> <20080111155733.GA3240@caradoc.them.org> <1200086736.26270.35.camel@gargoyle> <1201277155.11950.134.camel@localhost.localdomain> <200801261535.m0QFZddH026156@brahms.sibelius.xs4all.nl> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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: 2008-01/txt/msg00625.txt.bz2 On Sat, 26 Jan 2008, Mark Kettenis wrote: > > > GCC (XLC as well) doesn't promote floats to doubles and does not align > > > them to 8 bytes in the stack. Actually, it just aligns the prototyped > > > float parameters to 4 bytes in the stack. > > So both compilers are buggy. They would be buggy if they were targetting PowerPC Solaris from 1995 and if the 1995 ABI from Sun is an accurate description of the ABI on that system in the first place. They are not targetting that OS, they are targetting OSes where the 1995 document is only indicative guidance to a predecessor of the ABIs in use on those OSes. > > > This is something that needs to be improved in the ABI text. > > Well, I suppose you can change it, but I wouldn't call it an > improvement. Who controls the 32-bit PowerPC SystemV ABI these days? The Power.org ABI working group, which is working on producing a copyright-clean document (so not using any of the Sun text), copyrights to be assigned to the Linux Foundation, describing the ABIs (both hard and soft float, and E500 and Altivec extensions) as they are in use today for both GNU/Linux and bare-metal (EABI) targets (GNU/Linux and EABI differ in the default for -maix-struct-return, and in the default size of long double, but are otherwise the same at the function-call level). -- Joseph S. Myers joseph@codesourcery.com