From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) by sourceware.org (Postfix) with ESMTPS id DD6573857813 for ; Fri, 11 Dec 2020 05:51:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org DD6573857813 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=inria.fr Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=Paul.Zimmermann@inria.fr X-IronPort-AV: E=Sophos;i="5.78,410,1599516000"; d="scan'208";a="482352154" Received: from tomate.loria.fr (HELO tomate) ([152.81.10.51]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Dec 2020 06:51:33 +0100 Date: Fri, 11 Dec 2020 06:51:33 +0100 Message-Id: From: Paul Zimmermann To: newlib@sourceware.org Subject: huge powf error X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: newlib@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Newlib mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Dec 2020 05:51:36 -0000 Hi, while pursuing my analysis of the accuracy of mathematical libraries [1], I noticed that Newlib 3.3.0 powf(0x1.ffffeep-1,-0x1.000002p+27) gives +Inf instead of 0xe.a9a99p+100 which is largely inside the binary32 range. (The same issue appears with OpenLibm 0.7.0.) Best regards, Paul Zimmermann [1] https://homepages.loria.fr/PZimmermann/papers/#accuracy