1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- 2 * 3 * ***** BEGIN LICENSE BLOCK ***** 4 * Version: MPL 1.1/GPL 2.0/LGPL 2.1 5 * 6 * The contents of this file are subject to the Mozilla Public License Version 7 * 1.1 (the "License"); you may not use this file except in compliance with 8 * the License. You may obtain a copy of the License at 9 * http://www.mozilla.org/MPL/ 10 * 11 * Software distributed under the License is distributed on an "AS IS" basis, 12 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License 13 * for the specific language governing rights and limitations under the 14 * License. 15 * 16 * The Original Code is Mozilla Communicator client code, released 17 * March 31, 1998. 18 * 19 * The Initial Developer of the Original Code is 20 * Sun Microsystems, Inc. 21 * Portions created by the Initial Developer are Copyright (C) 1998 22 * the Initial Developer. All Rights Reserved. 23 * 24 * Contributor(s): 25 * 26 * Alternatively, the contents of this file may be used under the terms of 27 * either of the GNU General Public License Version 2 or later (the "GPL"), 28 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), 29 * in which case the provisions of the GPL or the LGPL are applicable instead 30 * of those above. If you wish to allow use of your version of this file only 31 * under the terms of either the GPL or the LGPL, and not to allow others to 32 * use your version of this file under the terms of the MPL, indicate your 33 * decision by deleting the provisions above and replace them with the notice 34 * and other provisions required by the GPL or the LGPL. If you do not delete 35 * the provisions above, a recipient may use your version of this file under 36 * the terms of any one of the MPL, the GPL or the LGPL. 37 * 38 * ***** END LICENSE BLOCK ***** */ 39 40 /* @(#)e_sinh.c 1.3 95/01/18 */ 41 /* 42 * ==================================================== 43 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 44 * 45 * Developed at SunSoft, a Sun Microsystems, Inc. business. 46 * Permission to use, copy, modify, and distribute this 47 * software is freely granted, provided that this notice 48 * is preserved. 49 * ==================================================== 50 */ 51 52 /* __ieee754_sinh(x) 53 * Method : 54 * mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2 55 * 1. Replace x by |x| (sinh(-x) = -sinh(x)). 56 * 2. 57 * E + E/(E+1) 58 * 0 <= x <= 22 : sinh(x) := --------------, E=expm1(x) 59 * 2 60 * 61 * 22 <= x <= lnovft : sinh(x) := exp(x)/2 62 * lnovft <= x <= ln2ovft: sinh(x) := exp(x/2)/2 * exp(x/2) 63 * ln2ovft < x : sinh(x) := x*shuge (overflow) 64 * 65 * Special cases: 66 * sinh(x) is |x| if x is +INF, -INF, or NaN. 67 * only sinh(0)=0 is exact for finite x. 68 */ 69 70 #include "fdlibm.h" 71 72 #ifdef __STDC__ 73 static const double one = 1.0, shuge = 1.0e307; 74 #else 75 static double one = 1.0, shuge = 1.0e307; 76 #endif 77 78 #ifdef __STDC__ __ieee754_sinh(double x)79 double __ieee754_sinh(double x) 80 #else 81 double __ieee754_sinh(x) 82 double x; 83 #endif 84 { 85 fd_twoints u; 86 double t,w,h; 87 int ix,jx; 88 unsigned lx; 89 90 /* High word of |x|. */ 91 u.d = x; 92 jx = __HI(u); 93 ix = jx&0x7fffffff; 94 95 /* x is INF or NaN */ 96 if(ix>=0x7ff00000) return x+x; 97 98 h = 0.5; 99 if (jx<0) h = -h; 100 /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */ 101 if (ix < 0x40360000) { /* |x|<22 */ 102 if (ix<0x3e300000) /* |x|<2**-28 */ 103 if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */ 104 t = fd_expm1(fd_fabs(x)); 105 if(ix<0x3ff00000) return h*(2.0*t-t*t/(t+one)); 106 return h*(t+t/(t+one)); 107 } 108 109 /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */ 110 if (ix < 0x40862E42) return h*__ieee754_exp(fd_fabs(x)); 111 112 /* |x| in [log(maxdouble), overflowthresold] */ 113 lx = *( (((*(unsigned*)&one)>>29)) + (unsigned*)&x); 114 if (ix<0x408633CE || (ix==0x408633ce)&&(lx<=(unsigned)0x8fb9f87d)) { 115 w = __ieee754_exp(0.5*fd_fabs(x)); 116 t = h*w; 117 return t*w; 118 } 119 120 /* |x| > overflowthresold, sinh(x) overflow */ 121 return x*shuge; 122 } 123