From mboxrd@z Thu Jan  1 00:00:00 1970
X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/4823
Path: news.gmane.org!not-for-mail
From: Morten Welinder <mwelinder@gmail.com>
Newsgroups: gmane.linux.lib.musl.general
Subject: Re: printf issues
Date: Mon, 7 Apr 2014 09:40:53 -0400
Message-ID: <CANv4PN=MvbcrCv28Z=+3BumvtivELh_teUp=O6Ogfu7Aob2CTQ@mail.gmail.com>
References: <20140404141515.GD3034@port70.net>
	<CANv4PNk=i5fx62bK3SHdusu1kWm9yU26qMnVHYYmnL74=DACig@mail.gmail.com>
	<20140404150705.GN26358@brightrain.aerifal.cx>
	<CANv4PN=LsCLdOmgUwx5JD=cCVj3+KWDj3c-KRexjLNY4xZShPw@mail.gmail.com>
	<20140404185413.GH3034@port70.net>
	<CANv4PNm6NtK13K3T51TCznFiZ2C4qxnvFN4xMFRDAdasA4wGUw@mail.gmail.com>
	<CANv4PN=Ch=EaeD6=sWZvOAf6wpH8HDhDbK+sp4Vroa0XB29PcA@mail.gmail.com>
	<20140404210837.GS26358@brightrain.aerifal.cx>
	<CANv4PNm6wUonre6PXY_9qqPnrPNw7ouL0Rta47Jn8vGC_6ZE=w@mail.gmail.com>
	<CANv4PNmMWBnvh_B25L=R_sv5w9jbCxA+tK8+c9i9qcSgc_ucJw@mail.gmail.com>
	<20140407072930.GB26358@brightrain.aerifal.cx>
Reply-To: musl@lists.openwall.com
NNTP-Posting-Host: plane.gmane.org
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
X-Trace: ger.gmane.org 1396878076 19595 80.91.229.3 (7 Apr 2014 13:41:16 GMT)
X-Complaints-To: usenet@ger.gmane.org
NNTP-Posting-Date: Mon, 7 Apr 2014 13:41:16 +0000 (UTC)
To: musl@lists.openwall.com
Original-X-From: musl-return-4827-gllmg-musl=m.gmane.org@lists.openwall.com Mon Apr 07 15:41:08 2014
Return-path: <musl-return-4827-gllmg-musl=m.gmane.org@lists.openwall.com>
Envelope-to: gllmg-musl@plane.gmane.org
Original-Received: from mother.openwall.net ([195.42.179.200])
	by plane.gmane.org with smtp (Exim 4.69)
	(envelope-from <musl-return-4827-gllmg-musl=m.gmane.org@lists.openwall.com>)
	id 1WX9nQ-0005OD-Ii
	for gllmg-musl@plane.gmane.org; Mon, 07 Apr 2014 15:41:08 +0200
Original-Received: (qmail 28443 invoked by uid 550); 7 Apr 2014 13:41:06 -0000
Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm
Precedence: bulk
List-Post: <mailto:musl@lists.openwall.com>
List-Help: <mailto:musl-help@lists.openwall.com>
List-Unsubscribe: <mailto:musl-unsubscribe@lists.openwall.com>
List-Subscribe: <mailto:musl-subscribe@lists.openwall.com>
Original-Received: (qmail 28426 invoked from network); 7 Apr 2014 13:41:05 -0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20120113;
        h=mime-version:in-reply-to:references:date:message-id:subject:from:to
         :content-type;
        bh=SpIeyNfdcTJkyjjn+ivFfJM9D09O5ZE/wo/h8oi5fiM=;
        b=C/wr6vS6zGUrSpRPJk5aeBK+UiPIDvMmsVijCLBE0WuVZ/jGOlzQdtM4K37ZVPNbaZ
         sJ2fOJq8HoVZipDpNzGee4TrLO/Zg+PI2zQ91Es36JKCePu/zjTtZoz7dKzJhCGNgw8L
         dpJlkozBogwY07dNeyQJKj7Hv6L4YZVHj/Oe5OIzobvfMkTE4uxCCMDWXAFjVSQtClxb
         gDIoPZrR1Z4P4gabq1gsGE2BxH/SP2I985GMUdoVHFs7ypUly35Yn0YqpCILdO0XqJr/
         55yiUOSWMVUTUO2o22K8I6/IPak4Qd1j0vjSCdqQ6lNTizl99bu2+yQuJZPOZ5+imWp7
         s1+A==
X-Received: by 10.194.58.180 with SMTP id s20mr42457530wjq.54.1396878053961;
 Mon, 07 Apr 2014 06:40:53 -0700 (PDT)
In-Reply-To: <20140407072930.GB26358@brightrain.aerifal.cx>
Xref: news.gmane.org gmane.linux.lib.musl.general:4823
Archived-At: <http://permalink.gmane.org/gmane.linux.lib.musl.general/4823>

I am seeing another case of printing the wrong result.  (This is with
the pre-fix code, but I don't think that matters.)

For 0xc.301316272b908p+49L (aka 6861116509411105.0L) with format
"%.15Lg" I get

musl: 6.86111650941111e+15
glibc: 6.8611165094111e+15

Musl has rounded to odd here for a midpoint case.

Morten







On Mon, Apr 7, 2014 at 3:29 AM, Rich Felker <dalias@aerifal.cx> wrote:
> On Fri, Apr 04, 2014 at 08:01:00PM -0400, Morten Welinder wrote:
>> I *think* the right fix is to add the following "if' statement into
>> the rounding loop:
>>
>>                 while (*d > 999999999) {
>>                     *d--=0;
>>                     if (d < a) *--a = 0;
>>                     (*d)++;
>>                 }
>>
>> This also ought to make the d<a test afterwards unnecessary.  But
>> more tests would be better.
>
> After re-studying the code, I think this is the correct fix, and I've
> committed the fix to git. I also fixed the bug where %g failed to trim
> trailing zeros.
>
> Rich