From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.2 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by inbox.vuxu.org (OpenSMTPD) with SMTP id 79871e1d for ; Tue, 14 Jan 2020 18:51:11 +0000 (UTC) Received: (qmail 11951 invoked by uid 550); 14 Jan 2020 18:51:10 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 11933 invoked from network); 14 Jan 2020 18:51:09 -0000 Date: Tue, 14 Jan 2020 19:50:58 +0100 From: Szabolcs Nagy To: musl@lists.openwall.com Message-ID: <20200114185058.GV23985@port70.net> Mail-Followup-To: musl@lists.openwall.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [musl] Q: dealing with missing removal of excess precision * Alexander Monakov [2020-01-14 21:17:55 +0300]: > What to do with functions that return values with excess precision from asm? > > Many of the remaining x87-based asm implementations do not remove excess > precision on return. This looks like a bug, but matches Glibc behavior. > Moving such functions to C would either introduce removal of excess precision, > or result in code that lies to the compiler by pretending that inline asm keeps > values within precision of float/double, where in reality it might not. the intention is to remove excess precision so it's good that's happening. otoh it would be nice if there was a way to tell the compiler not to remove it (e.g. in case the asm already took care of it) even in c99 standard mode.