From owner-sc22wg5@open-std.org Mon Feb 25 21:44:48 2008 Return-Path: X-Original-To: sc22wg5-dom6 Delivered-To: sc22wg5-dom6@open-std.org Received: by open-std.org (Postfix, from userid 521) id AA5C0D8911; Mon, 25 Feb 2008 21:44:48 +0100 (CET) X-Original-To: sc22wg5@open-std.org Delivered-To: sc22wg5@open-std.org Received: from nmta3.jpl.nasa.gov (nmta.jpl.nasa.gov [137.78.160.108]) by open-std.org (Postfix) with ESMTP id 72E2738508 for ; Mon, 25 Feb 2008 21:44:13 +0100 (CET) Received: from xmta2.jpl.nasa.gov (xmta2.jpl.nasa.gov [137.78.160.56]) by nmta3.jpl.nasa.gov (Switch-3.2.6/Switch-3.2.6) with ESMTP id m1PKi2a7030663 for ; Mon, 25 Feb 2008 12:44:04 -0800 Received: from mprox2.jpl.nasa.gov (mprox2.jpl.nasa.gov [137.78.160.141]) by xmta2.jpl.nasa.gov (Switch-3.2.6/Switch-3.2.6) with ESMTP id m1PKhxlI009325 for ; Mon, 25 Feb 2008 12:44:01 -0800 Received: from [137.79.7.57] (math.jpl.nasa.gov [137.79.7.57]) (authenticated bits=0) by mprox2.jpl.nasa.gov (Switch-3.2.6/Switch-3.2.6) with ESMTP id m1PKhtCG010843 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NOT) for ; Mon, 25 Feb 2008 12:43:57 -0800 Subject: [Fwd: Fwd: [Numeric-interest] IEEE 754R revision effort] From: Van Snyder Reply-To: Van.Snyder@jpl.nasa.gov To: sc22wg5 Content-Type: text/plain; charset=ISO-8859-1 Organization: Yes Date: Mon, 25 Feb 2008 12:43:55 -0800 Message-Id: <1203972235.3671.347.camel@math.jpl.nasa.gov> Mime-Version: 1.0 X-Mailer: Evolution 2.8.0 (2.8.0-40.el5) Content-Transfer-Encoding: 8bit X-Source-IP: math.jpl.nasa.gov [137.79.7.57] X-Source-Sender: Van.Snyder@jpl.nasa.gov X-AUTH: Authorized Sender: owner-sc22wg5@open-std.org Precedence: bulk This is a letter from David Hough concerning IEEE 754r that I received via IFIP WG 2.5. Van ======================================================================== Bo Einarsson Mathematics Department Linköpings universitet SE-581 83 Linköping, SWEDEN ------ Forwarded message ------- From: David Hough 754R work <754r@ucbtest.org> To: numeric-interest@ucbtest.org Date: Fri, 22 Feb 2008 11:27:58 -0800 (PST) The IEEE 754R revision effort has entered its eighth year. All the active participants are pretty tired and would like to wrap things up as quickly as possible. However I see no value in publishing in haste and repenting at leisure while trying to explain specifications that are ambiguous or obscure. I am particularly concerned about issues around expression evaluation and the mapping of programming language expressions into operations of the draft standard. 754's unspecification in this area has led to 20 years of misunderstandings, particularly around higher intermediate precision. But there can be opposition to rewriting ambiguous text, even rewriting which is not supposed to change the specification, since a clarification might meet one person's presuppositions and not another's, and hence might precipitate further review cycles. It would help me determine whether I am on the right track or jousting at windmills if some individuals from the technical computing application writing, mathematical software libraries, language design, and language implementation communities would take a fresh look at the troublesome areas and say what they think. I have already read the comments from persons on the IEEE 754R sponsor ballot group, on which chip and system implementors are well represented. I have written a long evaluation of the current draft 1.6.0 covering high-level issues: http://754r.ucbtest.org/msc-ballots/ballot5.html which also has some low-level nitpicking, and also a list of lost causes - things that seem suboptimal but unfixable. I am currently most concerned with draft 1.6.0 clause 10 and clause 5.4.1. Some of my commentaries are in the form of proposed strikeouts in green and proposed additions in red: http://754r.ucbtest.org/msc-ballots/clause10.pdf http://754r.ucbtest.org/msc-ballots/formatof.pdf but they may be hard to interpret without the context of a whole draft. Draft 1.6.0 isn't publicly accessible, so if you need it, you must request a review copy from Bob Davis (bob@scsi.com). An older draft 1.5.0 is available at http://754r.ucbtest.org/drafts/archive/2007-10-05.pdf which has a number of differences from 1.6.0, but not many in these particular clauses. _______________________________________________ Numeric-interest mailing list Numeric-interest@ucbtest.org http://mailman.oakapple.net/mailman/listinfo/numeric-interest