From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from esa2.mentor.iphmx.com (esa2.mentor.iphmx.com [68.232.141.98]) by sourceware.org (Postfix) with ESMTPS id 4E59F3982C2D for ; Thu, 24 Jun 2021 18:02:16 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 4E59F3982C2D Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=codesourcery.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=mentor.com IronPort-SDR: s2ErDgl39H0AdGJRbflrECIHtJR/rAGZFvn/xWTHJ54hFiJ69QZBY7yi4i6sNBZHq1fEBH1akW 9TVgfHjDllU3xhaOt1RdhBQBLC9dOWTO0dYwPsUX6GNZ8dOeW/ETDli01zkoBGTM4Ld3rvIiz2 itD26+CZr2gamBrzIXNssoOWuI5zYFKzhUlyCA3KatiNL4OpY38dXgib5I4pXORqYIl92rmqfK dlrTD6tLOaSEJnyOaEARNk/TVTauj5Wgl3pii/TM/McwQsULz8jxgvnWQ5bRghr+2P05r6O8gY 9pU= X-IronPort-AV: E=Sophos;i="5.83,296,1616486400"; d="scan'208";a="62796700" Received: from orw-gwy-02-in.mentorg.com ([192.94.38.167]) by esa2.mentor.iphmx.com with ESMTP; 24 Jun 2021 10:02:15 -0800 IronPort-SDR: r+tEUe9MTcDHhz3R8hWfEEX8JkPgpqhcf+2xSoVZndiJyFib0EmYvsTkcRsZ/eLM6bkUVwq9tm 3surlw0YAFz3w1BGSqVyJ5uQQrn0I+z+HOOeOT8pHINOs2OiW4QkMBuujXNsypAkzjlkpa1H8q ZB3fL45m77KnQeecixSB1P1bmppd/XFsRl08rN/Jp+m69pa7orKFYhsxw3fDzLX7+6/nFn8THF 6KZRCWRhs7on7wvyj+5Qgkv0iAUftrODOW6VptpTZzcELpvcAwCSZYni/pahv1G2unH8SKDDPM /8o= Date: Thu, 24 Jun 2021 18:02:11 +0000 From: Joseph Myers X-X-Sender: jsm28@digraph.polyomino.org.uk To: Paul Zimmermann CC: Subject: Re: values of FE_TONEAREST... In-Reply-To: Message-ID: References: User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-Originating-IP: [137.202.0.90] X-ClientProxiedBy: svr-ies-mbx-09.mgc.mentorg.com (139.181.222.9) To svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) X-Spam-Status: No, score=-3120.4 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Jun 2021 18:02:17 -0000 On Thu, 24 Jun 2021, Paul Zimmermann wrote: > Hi, > > I'd like to have the opinion of GNU libc developers on this, especially those > who are also involved in Redhat Newlib: > > https://mailman.oakapple.net/pipermail/cfp-interest/2021-June/002038.html You're only quoting the x86 values there. glibc has 17 architecture-specific bits/fenv.h headers, and most architectures have their own values of the rounding mode macros that directly correspond to that architecture's bits in the control register (and are different from those for all other architectures). (AArch64 and Arm share the values of the macros. So do MIPS and PowerPC and S/390.) That's before you get into complications of different architectures supporting different sets of rounding modes. (RISC-V has the hardware support needed for FE_TONEARESTFROMZERO, though various glibc code and tests that handle all the standard rounding modes would need updating to handle that one as well before a definition of FE_TONEARESTFROMZERO could be added and work reliably. PowerPC hardware supports eight decimal rounding modes, not just the IEEE five.) -- Joseph S. Myers joseph@codesourcery.com