From owner-cvs-src@FreeBSD.ORG Thu Feb 14 10:23:52 2008 Return-Path: Delivered-To: cvs-src@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1CE7B16A421; Thu, 14 Feb 2008 10:23:52 +0000 (UTC) (envelope-from bde@FreeBSD.org) Received: from repoman.freebsd.org (repoman.freebsd.org [IPv6:2001:4f8:fff6::29]) by mx1.freebsd.org (Postfix) with ESMTP id 00CBC13C47E; Thu, 14 Feb 2008 10:23:52 +0000 (UTC) (envelope-from bde@FreeBSD.org) Received: from repoman.freebsd.org (localhost [127.0.0.1]) by repoman.freebsd.org (8.14.1/8.14.1) with ESMTP id m1EANpik042955; Thu, 14 Feb 2008 10:23:51 GMT (envelope-from bde@repoman.freebsd.org) Received: (from bde@localhost) by repoman.freebsd.org (8.14.1/8.14.1/Submit) id m1EANpxr042954; Thu, 14 Feb 2008 10:23:51 GMT (envelope-from bde) Message-Id: <200802141023.m1EANpxr042954@repoman.freebsd.org> From: Bruce Evans Date: Thu, 14 Feb 2008 10:23:51 +0000 (UTC) To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org X-FreeBSD-CVS-Branch: HEAD Cc: Subject: cvs commit: src/lib/msun/src e_powf.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Feb 2008 10:23:52 -0000 bde 2008-02-14 10:23:51 UTC FreeBSD src repository Modified files: lib/msun/src e_powf.c Log: Fix the hi+lo decomposition for 2/(3ln2). The decomposition needs to be into 12+24 bits of precision for extra-precision multiplication, but was into 13+24 bits. On i386 with -O1 the bug was hidden by accidental extra precision, but on amd64, in 2^32 trials the bug caused about 200000 errors of more than 1 ulp, with a maximum error of about 80 ulps. Now the maximum error in 2^32 trials on amd64 is 0.8573 ulps. It is still 0.8316 ulps on i386 with -O1. The nearby decomposition of 1/ln2 and the decomposition of 2/(3ln2) in the double precision version seem to be sub-optimal but not broken. Revision Changes Path 1.14 +2 -2 src/lib/msun/src/e_powf.c