From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/650 Path: news.gmane.org!not-for-mail From: Szabolcs Nagy Newsgroups: gmane.linux.lib.musl.general Subject: Re: correctly rounded sqrt Date: Wed, 14 Mar 2012 20:01:23 +0100 Message-ID: <20120314190123.GH5728@port70.net> References: <20120314165604.GF5728@port70.net> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: dough.gmane.org 1331751700 19331 80.91.229.3 (14 Mar 2012 19:01:40 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Wed, 14 Mar 2012 19:01:40 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-651-gllmg-musl=m.gmane.org@lists.openwall.com Wed Mar 14 20:01:39 2012 Return-path: 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 ) id 1S7tS3-0007hi-LA for gllmg-musl@plane.gmane.org; Wed, 14 Mar 2012 20:01:35 +0100 Original-Received: (qmail 1388 invoked by uid 550); 14 Mar 2012 19:01:35 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 1380 invoked from network); 14 Mar 2012 19:01:35 -0000 Content-Disposition: inline In-Reply-To: <20120314165604.GF5728@port70.net> User-Agent: Mutt/1.5.21 (2010-09-15) Xref: news.gmane.org gmane.linux.lib.musl.general:650 Archived-At: * Szabolcs Nagy [2012-03-14 17:56:05 +0100]: > i tried to solve the sqrt issue with a wrapper > as discussed on irc, but i couldn't find a nice > solution > i did some benchmarks: (1x == single sqrt instruction) wrapped sqrt is about 3.5x the fdlibm software sqrt is about 10x fp precision setting is about 1.2x it might be possible to do a bit better wrapping but not much better, so fp prec setting wins if that's feasible..