From owner-freebsd-numerics@FreeBSD.ORG Sun Aug 12 22:58:35 2012 Return-Path: <owner-freebsd-numerics@FreeBSD.ORG> Delivered-To: freebsd-numerics@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 09727106564A for <freebsd-numerics@freebsd.org>; Sun, 12 Aug 2012 22:58:35 +0000 (UTC) (envelope-from peter@rulingia.com) Received: from vps.rulingia.com (host-122-100-2-194.octopus.com.au [122.100.2.194]) by mx1.freebsd.org (Postfix) with ESMTP id 96B518FC14 for <freebsd-numerics@freebsd.org>; Sun, 12 Aug 2012 22:58:34 +0000 (UTC) Received: from server.rulingia.com (c220-239-249-137.belrs5.nsw.optusnet.com.au [220.239.249.137]) by vps.rulingia.com (8.14.5/8.14.5) with ESMTP id q7CMwY8W075534 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for <freebsd-numerics@freebsd.org>; Mon, 13 Aug 2012 08:58:34 +1000 (EST) (envelope-from peter@rulingia.com) X-Bogosity: Ham, spamicity=0.000000 Received: from server.rulingia.com (localhost.rulingia.com [127.0.0.1]) by server.rulingia.com (8.14.5/8.14.5) with ESMTP id q7CMwSDk020953 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for <freebsd-numerics@freebsd.org>; Mon, 13 Aug 2012 08:58:28 +1000 (EST) (envelope-from peter@server.rulingia.com) Received: (from peter@localhost) by server.rulingia.com (8.14.5/8.14.5/Submit) id q7CMwS4j020952 for freebsd-numerics@freebsd.org; Mon, 13 Aug 2012 08:58:28 +1000 (EST) (envelope-from peter) Resent-From: Peter Jeremy <peter@rulingia.com> Resent-Date: Mon, 13 Aug 2012 08:58:28 +1000 Resent-Message-ID: <20120812225828.GO20453@server.rulingia.com> Resent-To: freebsd-numerics@freebsd.org Received: from vps.rulingia.com (host-122-100-2-194.octopus.com.au [122.100.2.194]) by server.rulingia.com (8.14.5/8.14.5) with ESMTP id q6K4U9Tk025066 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for <peter@home.rulingia.com>; Fri, 20 Jul 2012 14:30:10 +1000 (EST) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) by vps.rulingia.com (8.14.5/8.14.5) with ESMTP id q6K4U6Lg085380 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for <peter@rulingia.com>; Fri, 20 Jul 2012 14:30:08 +1000 (EST) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (localhost.apl.washington.edu [127.0.0.1]) by troutmask.apl.washington.edu (8.14.5/8.14.5) with ESMTP id q6K4U5gK007441; Thu, 19 Jul 2012 21:30:05 -0700 (PDT) (envelope-from sgk@troutmask.apl.washington.edu) Received: (from sgk@localhost) by troutmask.apl.washington.edu (8.14.5/8.14.5/Submit) id q6K4U4B9007440; Thu, 19 Jul 2012 21:30:04 -0700 (PDT) (envelope-from sgk) From: Steve Kargl <sgk@troutmask.apl.washington.edu> Mail-Followup-To: freebsd-numerics@freebsd.org To: Bruce Evans <brde@optusnet.com.au> Message-ID: <20120720043004.GA7404@troutmask.apl.washington.edu> References: <20120717040118.GA86840@troutmask.apl.washington.edu> <20120717042125.GF66913@server.rulingia.com> <20120717043848.GB87001@troutmask.apl.washington.edu> <20120717225328.GA86902@server.rulingia.com> <20120717232740.GA95026@troutmask.apl.washington.edu> <20120718001337.GA87817@server.rulingia.com> <20120718123627.D1575@besplex.bde.org> <20120719213944.GA21199@server.rulingia.com> <20120719234425.GA6280@troutmask.apl.washington.edu> <20120720130309.P814@besplex.bde.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120720130309.P814@besplex.bde.org> User-Agent: Mutt/1.4.2.3i Cc: Diane Bruce <db@db.net>, John Baldwin <jhb@freebsd.org>, David Chisnall <theraven@freebsd.org>, Stephen Montgomery-Smith <stephen@missouri.edu>, Bruce Evans <bde@freebsd.org>, David Schultz <das@freebsd.org>, Peter Jeremy <peter@rulingia.com>, Warner Losh <imp@bsdimp.com> Subject: Re: Use of C99 extra long double math functions after r236148 X-BeenThere: freebsd-numerics@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Discussions of high quality implementation of libm functions." <freebsd-numerics.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-numerics>, <mailto:freebsd-numerics-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-numerics> List-Post: <mailto:freebsd-numerics@freebsd.org> List-Help: <mailto:freebsd-numerics-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-numerics>, <mailto:freebsd-numerics-request@freebsd.org?subject=subscribe> Date: Sun, 12 Aug 2012 22:58:35 -0000 X-Original-Date: Thu, 19 Jul 2012 21:30:04 -0700 X-List-Received-Date: Sun, 12 Aug 2012 22:58:35 -0000 On Fri, Jul 20, 2012 at 02:12:20PM +1000, Bruce Evans wrote: > On Thu, 19 Jul 2012, Steve Kargl wrote: > > >I collected some of the float and double into a cheat sheet. > > > >Idioms used in libm with float type: > > > > int32_t xsb; > > u_int32_t hx; > > > > GET_FLOAT_WORD(hx, x); > > > > /* Get the sign bit of x */ > > xsb = (hx >> 31) & 1; > > Getting it without shifting it (hx & 0x8000) is more efficient and common. > You don't need to shift it in this example. I collected these from msun/src, when I was trying to understand the magic numbers. I suppose someone should audit the code for consistency. :-) laptop:kargl[219] grep " (hx>>31)&1" *c e_exp.c: xsb = (hx>>31)&1; /* sign bit of x */ e_expf.c: xsb = (hx>>31)&1; /* sign bit of x */ -- Steve