From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1814 invoked by alias); 27 Sep 2011 11:29:48 -0000 Received: (qmail 1806 invoked by uid 22791); 27 Sep 2011 11:29:48 -0000 X-SWARE-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mailgw12.technion.ac.il (HELO mailgw12.technion.ac.il) (132.68.225.12) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 27 Sep 2011 11:29:33 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvkCAFSzgU6ERAG2gWdsb2JhbABCpgWCBQEBFiYmgVMBAQU4QAEQCxgJFg8JAwIBAgFFBg0BBwEBwH+HCwSHbJEIgzWIYA Received: from tx2.technion.ac.il (HELO techunix.technion.ac.il) ([132.68.1.182]) by mailgw12.technion.ac.il with ESMTP; 27 Sep 2011 14:29:17 +0300 Received: from [127.0.0.1] (tx1.technion.ac.il [132.68.1.180]) by techunix.technion.ac.il (Postfix) with ESMTP id 611A332C195; Tue, 27 Sep 2011 14:29:17 +0300 (IDT) Message-ID: <4E81B38D.5000705@tx.technion.ac.il> Date: Tue, 27 Sep 2011 18:27:00 -0000 From: Michael Veksler User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.22) Gecko/20110906 Fedora/3.1.14-1.fc14 Lightning/1.0b2 Thunderbird/3.1.14 MIME-Version: 1.0 To: Ian Lance Taylor CC: Michael Veksler , gcc-help@gcc.gnu.org Subject: Re: sizeof(long double) vs. std::numeric_limits and x86-64 vs x86 References: <4E80F88F.2050608@tx.technion.ac.il> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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: 2011-09/txt/msg00222.txt.bz2 On 09/27/2011 01:46 AM, Ian Lance Taylor wrote: > Alas, no. On x86_64 long double is an 80-bit floating point number, > just as on 32-bit x86. The size is 16 bytes because the x86_64 prefers > to align large values to 8-byte boundaries. > > gcc works this way because the 80-bit floating point format is supported > directly in hardware, unlike the 128-bit format. > > I suspected that this is the case, but hoped for the better. Thanks -- Michael