From owner-freebsd-bugs@FreeBSD.ORG  Thu Jul 14 18:54:38 2005
Return-Path: <owner-freebsd-bugs@FreeBSD.ORG>
X-Original-To: freebsd-bugs@FreeBSD.ORG
Delivered-To: freebsd-bugs@FreeBSD.ORG
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 3841C16A41C;
	Thu, 14 Jul 2005 18:54:38 +0000 (GMT) (envelope-from das@FreeBSD.ORG)
Received: from VARK.MIT.EDU (VARK.MIT.EDU [18.95.3.179])
	by mx1.FreeBSD.org (Postfix) with ESMTP id CE29243D46;
	Thu, 14 Jul 2005 18:54:37 +0000 (GMT) (envelope-from das@FreeBSD.ORG)
Received: from VARK.MIT.EDU (localhost [127.0.0.1])
	by VARK.MIT.EDU (8.13.3/8.13.1) with ESMTP id j6EIqPOI095384;
	Thu, 14 Jul 2005 14:52:25 -0400 (EDT) (envelope-from das@FreeBSD.ORG)
Received: (from das@localhost)
	by VARK.MIT.EDU (8.13.3/8.13.1/Submit) id j6EIqPk8095383;
	Thu, 14 Jul 2005 14:52:25 -0400 (EDT) (envelope-from das@FreeBSD.ORG)
Date: Thu, 14 Jul 2005 14:52:24 -0400
From: David Schultz <das@FreeBSD.ORG>
To: Mark Linimon <linimon@FreeBSD.ORG>
Message-ID: <20050714185224.GA95312@VARK.MIT.EDU>
Mail-Followup-To: Mark Linimon <linimon@FreeBSD.ORG>,
	freebsd-bugs@FreeBSD.ORG, freebsd-standards@FreeBSD.ORG
References: <200409010324.i813OjTi063637@freefall.freebsd.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <200409010324.i813OjTi063637@freefall.freebsd.org>
Cc: freebsd-bugs@FreeBSD.ORG, freebsd-standards@FreeBSD.ORG
Subject: Re: misc/35381: incorrect floating-point display of large values
	when using round-upward IEEE mode
X-BeenThere: freebsd-bugs@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Bug reports <freebsd-bugs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-bugs>,
	<mailto:freebsd-bugs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-bugs>
List-Post: <mailto:freebsd-bugs@freebsd.org>
List-Help: <mailto:freebsd-bugs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-bugs>,
	<mailto:freebsd-bugs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 14 Jul 2005 18:54:38 -0000

This does not occur in FreeBSD 5.X.  It's unlikely that the issue
will be fixed in 4.X because the fix involves importing an updated
version of a library and making substantial changes to libc.

I reported some related problems to the author of gdtoa (which is
the library we use to perform this type of conversion) some months
ago.  These bugs affect 5.X and 6-CURRENT, although technically
speaking fixing them is not required (only recommended) by POSIX.

| - When FLT_ROUNDS is 3 (round downward), strtod() converts
|   the string "0x1.ffffffffffffffp0" to 2.  The correct   
|   result is   0x1.fffffffffffffp0.
| 
| - When FLT_ROUNDS is 3, strtopx() converts the string
|   "1.999999999999999999999999999999999" to 2.  Strtod(),
|   on the other hand, correctly rounds down.
| 
| - When FLT_ROUNDS is 2 (round upward), strtod() converts
|   the string "0x1.23p-5000" to 0.  The correct result
|   when rounding upwards is the smallest representable
|   number, 0x1p-1074.