From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 6547 invoked by alias); 29 Apr 2013 17:30:18 -0000 Mailing-List: contact glibc-bugs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: glibc-bugs-owner@sourceware.org Received: (qmail 6488 invoked by uid 48); 29 Apr 2013 17:30:16 -0000 From: "bugdal at aerifal dot cx" To: glibc-bugs@sourceware.org Subject: [Bug math/14412] Removal of sysdeps/x86_64/fpu/s_sincos.S causes regressions Date: Mon, 29 Apr 2013 17:30:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: glibc X-Bugzilla-Component: math X-Bugzilla-Keywords: X-Bugzilla-Severity: enhancement X-Bugzilla-Who: bugdal at aerifal dot cx X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: 2.18 X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 X-SW-Source: 2013-04/txt/msg00237.txt.bz2 http://sourceware.org/bugzilla/show_bug.cgi?id=14412 --- Comment #43 from Rich Felker 2013-04-29 17:30:14 UTC --- I don't have a copy of the latest IEEE 754 on hand (there's no free online version), but the consensus among implementors seems to be that a few special functions (such as sqrt) require correct rounding, and that the remaining functions (mostly transcendental) are required to give results with less than 1ulp of error. If sin(0x1p1000) is computed with incorrect argument reduction, it may have up to approximately 1e16 ulp error. Moreover, the C standard specifies: "2 The sin functions compute the sine of x (measured in radians). Returns 3 The sin functions return sin x." Without annex F, the C standard places no requirements on the precision or accuracy of floating point results (e.g. 2.0+2.0==5.0 is legal), but annex F recommends IEEE conforming behavior. If anyone else can provide some better citations, they'd be welcome. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.