1da2e3ebdSchin #include "FEATURE/uwin"
2da2e3ebdSchin 
3da2e3ebdSchin #if !_UWIN || _lib_asinh
4da2e3ebdSchin 
_STUB_asinh()5da2e3ebdSchin void _STUB_asinh(){}
6da2e3ebdSchin 
7da2e3ebdSchin #else
8da2e3ebdSchin 
9da2e3ebdSchin /*
10da2e3ebdSchin  * Copyright (c) 1985, 1993
11da2e3ebdSchin  *	The Regents of the University of California.  All rights reserved.
12da2e3ebdSchin  *
13da2e3ebdSchin  * Redistribution and use in source and binary forms, with or without
14da2e3ebdSchin  * modification, are permitted provided that the following conditions
15da2e3ebdSchin  * are met:
16da2e3ebdSchin  * 1. Redistributions of source code must retain the above copyright
17da2e3ebdSchin  *    notice, this list of conditions and the following disclaimer.
18da2e3ebdSchin  * 2. Redistributions in binary form must reproduce the above copyright
19da2e3ebdSchin  *    notice, this list of conditions and the following disclaimer in the
20da2e3ebdSchin  *    documentation and/or other materials provided with the distribution.
21da2e3ebdSchin  * 3. Neither the name of the University nor the names of its contributors
22da2e3ebdSchin  *    may be used to endorse or promote products derived from this software
23da2e3ebdSchin  *    without specific prior written permission.
24da2e3ebdSchin  *
25da2e3ebdSchin  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26da2e3ebdSchin  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27da2e3ebdSchin  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28da2e3ebdSchin  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29da2e3ebdSchin  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30da2e3ebdSchin  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31da2e3ebdSchin  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32da2e3ebdSchin  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33da2e3ebdSchin  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34da2e3ebdSchin  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35da2e3ebdSchin  * SUCH DAMAGE.
36da2e3ebdSchin  */
37da2e3ebdSchin 
38da2e3ebdSchin #ifndef lint
39da2e3ebdSchin static char sccsid[] = "@(#)asinh.c	8.1 (Berkeley) 6/4/93";
40da2e3ebdSchin #endif /* not lint */
41da2e3ebdSchin 
42da2e3ebdSchin /* ASINH(X)
43da2e3ebdSchin  * RETURN THE INVERSE HYPERBOLIC SINE OF X
44da2e3ebdSchin  * DOUBLE PRECISION (VAX D format 56 bits, IEEE DOUBLE 53 BITS)
45da2e3ebdSchin  * CODED IN C BY K.C. NG, 2/16/85;
46da2e3ebdSchin  * REVISED BY K.C. NG on 3/7/85, 3/24/85, 4/16/85.
47da2e3ebdSchin  *
48da2e3ebdSchin  * Required system supported functions :
49da2e3ebdSchin  *	copysign(x,y)
50da2e3ebdSchin  *	sqrt(x)
51da2e3ebdSchin  *
52da2e3ebdSchin  * Required kernel function:
53da2e3ebdSchin  *	log1p(x) 		...return log(1+x)
54da2e3ebdSchin  *
55da2e3ebdSchin  * Method :
56da2e3ebdSchin  *	Based on
57da2e3ebdSchin  *		asinh(x) = sign(x) * log [ |x| + sqrt(x*x+1) ]
58da2e3ebdSchin  *	we have
59da2e3ebdSchin  *	asinh(x) := x  if  1+x*x=1,
60da2e3ebdSchin  *		 := sign(x)*(log1p(x)+ln2))	 if sqrt(1+x*x)=x, else
61da2e3ebdSchin  *		 := sign(x)*log1p(|x| + |x|/(1/|x| + sqrt(1+(1/|x|)^2)) )
62da2e3ebdSchin  *
63da2e3ebdSchin  * Accuracy:
64da2e3ebdSchin  *	asinh(x) returns the exact inverse hyperbolic sine of x nearly rounded.
65da2e3ebdSchin  *	In a test run with 52,000 random arguments on a VAX, the maximum
66da2e3ebdSchin  *	observed error was 1.58 ulps (units in the last place).
67da2e3ebdSchin  *
68da2e3ebdSchin  * Constants:
69da2e3ebdSchin  * The hexadecimal values are the intended ones for the following constants.
70da2e3ebdSchin  * The decimal values may be used, provided that the compiler will convert
71da2e3ebdSchin  * from decimal to binary accurately enough to produce the hexadecimal values
72da2e3ebdSchin  * shown.
73da2e3ebdSchin  */
74da2e3ebdSchin #include "mathimpl.h"
75da2e3ebdSchin 
76da2e3ebdSchin vc(ln2hi, 6.9314718055829871446E-1  ,7217,4031,0000,f7d0,   0, .B17217F7D00000)
77da2e3ebdSchin vc(ln2lo, 1.6465949582897081279E-12 ,bcd5,2ce7,d9cc,e4f1, -39, .E7BCD5E4F1D9CC)
78da2e3ebdSchin 
79da2e3ebdSchin ic(ln2hi, 6.9314718036912381649E-1,   -1, 1.62E42FEE00000)
80da2e3ebdSchin ic(ln2lo, 1.9082149292705877000E-10, -33, 1.A39EF35793C76)
81da2e3ebdSchin 
82da2e3ebdSchin #ifdef vccast
83da2e3ebdSchin #define    ln2hi    vccast(ln2hi)
84da2e3ebdSchin #define    ln2lo    vccast(ln2lo)
85da2e3ebdSchin #endif
86da2e3ebdSchin 
87da2e3ebdSchin extern double asinh(x)
88da2e3ebdSchin double x;
89da2e3ebdSchin {
90da2e3ebdSchin 	double t,s;
91da2e3ebdSchin 	const static double	small=1.0E-10,	/* fl(1+small*small) == 1 */
92da2e3ebdSchin 				big  =1.0E20,	/* fl(1+big) == big */
93da2e3ebdSchin 				one  =1.0   ;
94da2e3ebdSchin 
95da2e3ebdSchin #if !defined(vax)&&!defined(tahoe)
96da2e3ebdSchin 	if(x!=x) return(x);	/* x is NaN */
97da2e3ebdSchin #endif	/* !defined(vax)&&!defined(tahoe) */
98da2e3ebdSchin 	if((t=copysign(x,one))>small)
99da2e3ebdSchin 	    if(t<big) {
100da2e3ebdSchin 	     	s=one/t; return(copysign(log1p(t+t/(s+sqrt(one+s*s))),x)); }
101da2e3ebdSchin 	    else	/* if |x| > big */
102da2e3ebdSchin 		{s=log1p(t)+ln2lo; return(copysign(s+ln2hi,x));}
103da2e3ebdSchin 	else	/* if |x| < small */
104da2e3ebdSchin 	    return(x);
105da2e3ebdSchin }
106da2e3ebdSchin 
107da2e3ebdSchin #endif
108