From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.tachyum.com (mx1.tachyum.com [66.160.133.170]) by sourceware.org (Postfix) with ESMTPS id 752A03861830 for ; Mon, 21 Jun 2021 20:44:47 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 752A03861830 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=tachyum.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=tachyum.com Received: by mx1.tachyum.com (Postfix, from userid 1000) id D0B611005693; Mon, 21 Jun 2021 13:44:45 -0700 (PDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 Received: from THQ-EX1.tachyum.com (unknown [10.7.1.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.tachyum.com (Postfix) with ESMTPS id 858E6100D44E; Mon, 21 Jun 2021 13:44:44 -0700 (PDT) Received: from THQ-EX1.tachyum.com (10.7.1.6) by THQ-EX1.tachyum.com (10.7.1.6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.14; Mon, 21 Jun 2021 13:44:44 -0700 Received: from THQ-EX1.tachyum.com ([10.7.1.6]) by THQ-EX1.tachyum.com ([10.7.1.6]) with mapi id 15.01.2176.014; Mon, 21 Jun 2021 13:44:44 -0700 From: Michael Morrell To: Joseph Myers CC: "libc-alpha@sourceware.org" Subject: RE: x86 Denormal flag Thread-Topic: x86 Denormal flag Thread-Index: Addkp0VeosYoV8xfRCOqycSuah/z4wCa4MIAAA4qW7A= Date: Mon, 21 Jun 2021 20:44:44 +0000 Message-ID: <27908b0e6bcd409ca29e418635908fff@tachyum.com> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.7.100.197] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 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: Mon, 21 Jun 2021 20:44:48 -0000 I guess I'm not convinced that adding the denormal operand flag in FE_ALL_E= XCEPT is bad. From a quick grep, I think this flag is defined in the follo= wing architectures: ia64 (FE_UNNORMAL), alpha (FE_DENORMAL), csky (__FE_DEN= ORMAL), and x86 (__FE_DENORM). AARCH64 also has this flag (the IDC bit in FPSR), but glibc does not define= an FE_ constant for it. For ia64, FE_ALL_EXCEPT includes FE_UNNORMAL, but none of the others seems = to include it so that is kind of inconsistent. Michael -----Original Message----- From: Joseph Myers =20 Sent: Monday, June 21, 2021 1:01 PM To: Michael Morrell Cc: libc-alpha@sourceware.org Subject: Re: x86 Denormal flag On Sat, 19 Jun 2021, Michael Morrell wrote: > It seems like fetestexcept only works for the 5 standard IEEE flags,=20 > but then why is __FE_DENORM even defined? It would probably be reasonable to move __FE_DENORM from an installed heade= r to an internal one that's only used by the fesetenv and fesetmode impleme= ntations that need to work on the environment (or the control mode parts of= the environment) as a whole, including implementation-defined parts of the= environment. I think including the "denormal operand" flag in FE_ALL_EXCEPT would be a b= ad idea, since it doesn't indicate any kind of exceptional condition in sta= ndard terms, and given that it's not in FE_ALL_EXCEPT, treating it as an ex= ception in other standard functions would be problematic. -- Joseph S. Myers joseph@codesourcery.com