1 /* @(#)s_asinh.c 5.1 93/09/24 */
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
10 * ====================================================
16 * asinh(x) = sign(x) * log [ |x| + sqrt(x*x+1) ]
18 * asinh(x) := x if 1+x*x=1,
19 * := sign(x)*(log(x)+ln2)) for large |x|, else
20 * := sign(x)*log(2|x|+1/(|x|+sqrt(x*x+1))) if|x|>2, else
21 * := sign(x)*log1p(|x| + x^2/(1 + sqrt(1+x^2)))
25 #include <math_private.h>
28 one = 1.00000000000000000000e+00, /* 0x3FF00000, 0x00000000 */
29 ln2 = 6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */
30 huge = 1.00000000000000000000e+300;
37 GET_HIGH_WORD (hx, x);
39 if (__builtin_expect (ix < 0x3e300000, 0)) /* |x|<2**-28 */
42 return x; /* return x inexact except 0 */
44 if (__builtin_expect (ix > 0x41b00000, 0)) /* |x| > 2**28 */
47 return x + x; /* x is inf or NaN */
48 w = __ieee754_log (fabs (x)) + ln2;
53 if (ix > 0x40000000) /* 2**28 > |x| > 2.0 */
55 w = __ieee754_log (2.0 * xa + one / (__ieee754_sqrt (xa * xa + one) +
58 else /* 2.0 > |x| > 2**-28 */
61 w = __log1p (xa + t / (one + __ieee754_sqrt (one + t)));
64 return __copysign (w, x);
66 weak_alias (__asinh, asinh)
68 strong_alias (__asinh, __asinhl)
69 weak_alias (__asinh, asinhl)