Open64 (mfef90, whirl2f, and IR tools)  TAG: version-openad; SVN changeset: 916
tanh.c
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00001 /*
00002 
00003   Copyright (C) 2000, 2001 Silicon Graphics, Inc.  All Rights Reserved.
00004 
00005   This program is free software; you can redistribute it and/or modify it
00006   under the terms of version 2.1 of the GNU Lesser General Public License 
00007   as published by the Free Software Foundation.
00008 
00009   This program is distributed in the hope that it would be useful, but
00010   WITHOUT ANY WARRANTY; without even the implied warranty of
00011   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
00012 
00013   Further, this software is distributed without any warranty that it is
00014   free of the rightful claim of any third person regarding infringement 
00015   or the like.  Any license provided herein, whether implied or 
00016   otherwise, applies only to this software file.  Patent licenses, if
00017   any, provided herein do not apply to combinations of this program with 
00018   other software, or any other product whatsoever.  
00019 
00020   You should have received a copy of the GNU Lesser General Public 
00021   License along with this program; if not, write the Free Software 
00022   Foundation, Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, 
00023   USA.
00024 
00025   Contact information:  Silicon Graphics, Inc., 1600 Amphitheatre Pky,
00026   Mountain View, CA 94043, or:
00027 
00028   http://www.sgi.com
00029 
00030   For further information regarding this notice, see:
00031 
00032   http://oss.sgi.com/projects/GenInfo/NoticeExplan
00033 
00034 */
00035 
00036 
00037 /*   VMS Compatibility Version  @(#)tanh.c      1.1    7/18/87
00038  */
00039 /*
00040         tanh(arg) computes the hyperbolic tangent of its floating
00041         point argument.
00042 
00043         sinh and cosh are called except for large arguments, which
00044         would cause overflow improperly.
00045 */
00046 #include "cmplrs/host.h"
00047 #include <math.h>
00048 #include "moremath.h"
00049 
00050 double_t
00051 tanh(doublt_t arg)
00052 {
00053         double_t sign;
00054 
00055         sign = 1.;
00056         if(arg < 0.){
00057                 arg = -arg;
00058                 sign = -1.;
00059         }
00060 
00061         if(arg > 21.)
00062                 return(sign);
00063 
00064         return(sign*sinh(arg)/cosh(arg));
00065 }
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