From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24399 invoked by alias); 28 Jun 2012 21:06:26 -0000 Received: (qmail 24302 invoked by uid 22791); 28 Jun 2012 21:06:23 -0000 X-SWARE-Spam-Status: No, hits=-2.7 required=5.0 tests=AWL,BAYES_00,KHOP_THREADED,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from terminus.zytor.com (HELO mail.zytor.com) (198.137.202.10) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 28 Jun 2012 21:06:00 +0000 Received: from tazenda.hos.anvin.org (c-67-188-81-177.hsd1.ca.comcast.net [67.188.81.177]) (authenticated bits=0) by mail.zytor.com (8.14.5/8.14.5) with ESMTP id q5SL5apQ012087 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=OK); Thu, 28 Jun 2012 14:05:36 -0700 Message-ID: <4FECC71F.50207@zytor.com> Date: Thu, 28 Jun 2012 21:06:00 -0000 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120615 Thunderbird/13.0.1 MIME-Version: 1.0 To: x32-abi@googlegroups.com CC: Mark Butler , "H.J. Lu" , discuss@x86-64.org, GCC Development , Binutils , GNU C Library , GDB Subject: Re: [x86-64 psABI] RFC: Extend x86-64 psABI to support x32 References: <4FEA131D.4090905@zytor.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2012-06/txt/msg00093.txt.bz2 On 06/28/2012 02:03 PM, Mark Butler wrote: > On Tuesday, June 26, 2012 1:53:01 PM UTC-6, H. Peter Anvin wrote: > > It's worth noting that there are *no* Linux platforms that are not > ILP32 > or LP64, so adding a third memory model is likely to cause even more > problems... > > > Care to comment on what sort of things would be likely to cause a large > number of problems porting to an L64P32 model? I understand that L32P64 > (as in Windows 64 bit) causes lots of problems, because there is a lot > of code that assumes that a pointer can be converted to a long and back. > That would not be a problem with L64P32 however, because there > pointers would be smaller than longs rather than larger. Every time you introduce a new model you will have problems, but in Linux it is a strong assumption that sizeof(long) == sizeof(void *). -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.