From mboxrd@z Thu Jan  1 00:00:00 1970
X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11869
Path: news.gmane.org!.POSTED!not-for-mail
From: Rich Felker <dalias@libc.org>
Newsgroups: gmane.linux.lib.musl.general
Subject: Re: [PATCH] math: rewrite fma with mostly int arithmetics
Date: Tue, 29 Aug 2017 22:04:30 -0400
Message-ID: <20170830020430.GC19925@brightrain.aerifal.cx>
References: <20170418224140.GN2082@port70.net>
 <20170422222425.GI17319@brightrain.aerifal.cx>
 <20170423110052.GQ2082@port70.net>
 <20170423151539.GO17319@brightrain.aerifal.cx>
 <20170423223448.GR2082@port70.net>
 <20170423223533.GS2082@port70.net>
Reply-To: musl@lists.openwall.com
NNTP-Posting-Host: blaine.gmane.org
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: blaine.gmane.org 1504058700 31362 195.159.176.226 (30 Aug 2017 02:05:00 GMT)
X-Complaints-To: usenet@blaine.gmane.org
NNTP-Posting-Date: Wed, 30 Aug 2017 02:05:00 +0000 (UTC)
User-Agent: Mutt/1.5.21 (2010-09-15)
To: musl@lists.openwall.com
Original-X-From: musl-return-11882-gllmg-musl=m.gmane.org@lists.openwall.com Wed Aug 30 04:04:51 2017
Return-path: <musl-return-11882-gllmg-musl=m.gmane.org@lists.openwall.com>
Envelope-to: gllmg-musl@m.gmane.org
Original-Received: from mother.openwall.net ([195.42.179.200])
	by blaine.gmane.org with smtp (Exim 4.84_2)
	(envelope-from <musl-return-11882-gllmg-musl=m.gmane.org@lists.openwall.com>)
	id 1dmsMw-0007G4-2C
	for gllmg-musl@m.gmane.org; Wed, 30 Aug 2017 04:04:38 +0200
Original-Received: (qmail 14151 invoked by uid 550); 30 Aug 2017 02:04:43 -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>
List-ID: <musl.lists.openwall.com>
Original-Received: (qmail 14133 invoked from network); 30 Aug 2017 02:04:42 -0000
Content-Disposition: inline
In-Reply-To: <20170423223533.GS2082@port70.net>
Original-Sender: Rich Felker <dalias@aerifal.cx>
Xref: news.gmane.org gmane.linux.lib.musl.general:11869
Archived-At: <http://permalink.gmane.org/gmane.linux.lib.musl.general/11869>

On Mon, Apr 24, 2017 at 12:35:33AM +0200, Szabolcs Nagy wrote:
> 			/* one bit is lost when scaled, add another top bit to
> 			   only round once at conversion if it is inexact */
> 			if (rhi << 53) {
> 				i = rhi>>1 | (rhi&1) | 1ull<<62;
> 				if (sign)
> 					i = -i;
> 				r = i;
> 				r = 2*r - c; /* remove top bit */
> 				volatile double uflow = DBL_MIN/FLT_MIN;
> 				uflow *= uflow;
> 			}

Is there any way to get rid of the volatile hack here?

Rich