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Diffstat (limited to 'src/third_party/js-1.7/fdlibm/e_atanh.c')
-rw-r--r-- | src/third_party/js-1.7/fdlibm/e_atanh.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/src/third_party/js-1.7/fdlibm/e_atanh.c b/src/third_party/js-1.7/fdlibm/e_atanh.c new file mode 100644 index 00000000000..dc4a90c8e03 --- /dev/null +++ b/src/third_party/js-1.7/fdlibm/e_atanh.c @@ -0,0 +1,110 @@ +/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * + * ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is Mozilla Communicator client code, released + * March 31, 1998. + * + * The Initial Developer of the Original Code is + * Sun Microsystems, Inc. + * Portions created by the Initial Developer are Copyright (C) 1998 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * + * Alternatively, the contents of this file may be used under the terms of + * either of the GNU General Public License Version 2 or later (the "GPL"), + * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +/* @(#)e_atanh.c 1.3 95/01/18 */ +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunSoft, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + * + */ + +/* __ieee754_atanh(x) + * Method : + * 1.Reduced x to positive by atanh(-x) = -atanh(x) + * 2.For x>=0.5 + * 1 2x x + * atanh(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------) + * 2 1 - x 1 - x + * + * For x<0.5 + * atanh(x) = 0.5*log1p(2x+2x*x/(1-x)) + * + * Special cases: + * atanh(x) is NaN if |x| > 1 with signal; + * atanh(NaN) is that NaN with no signal; + * atanh(+-1) is +-INF with signal. + * + */ + +#include "fdlibm.h" + +#ifdef __STDC__ +static const double one = 1.0, really_big = 1e300; +#else +static double one = 1.0, really_big = 1e300; +#endif + +static double zero = 0.0; + +#ifdef __STDC__ + double __ieee754_atanh(double x) +#else + double __ieee754_atanh(x) + double x; +#endif +{ + double t; + int hx,ix; + unsigned lx; + fd_twoints u; + u.d = x; + hx = __HI(u); /* high word */ + lx = __LO(u); /* low word */ + ix = hx&0x7fffffff; + if ((ix|((lx|(-(int)lx))>>31))>0x3ff00000) /* |x|>1 */ + return (x-x)/(x-x); + if(ix==0x3ff00000) + return x/zero; + if(ix<0x3e300000&&(really_big+x)>zero) return x; /* x<2**-28 */ + u.d = x; + __HI(u) = ix; /* x <- |x| */ + x = u.d; + if(ix<0x3fe00000) { /* x < 0.5 */ + t = x+x; + t = 0.5*fd_log1p(t+t*x/(one-x)); + } else + t = 0.5*fd_log1p((x+x)/(one-x)); + if(hx>=0) return t; else return -t; +} |