diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/s_tanh.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/s_tanh.c | 98 |
1 files changed, 0 insertions, 98 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_tanh.c b/sysdeps/ieee754/dbl-64/s_tanh.c deleted file mode 100644 index 344a2f0330..0000000000 --- a/sysdeps/ieee754/dbl-64/s_tanh.c +++ /dev/null @@ -1,98 +0,0 @@ -/* @(#)s_tanh.c 5.1 93/09/24 */ -/* - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunPro, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - */ - -#if defined(LIBM_SCCS) && !defined(lint) -static char rcsid[] = "$NetBSD: s_tanh.c,v 1.7 1995/05/10 20:48:22 jtc Exp $"; -#endif - -/* Tanh(x) - * Return the Hyperbolic Tangent of x - * - * Method : - * x -x - * e - e - * 0. tanh(x) is defined to be ----------- - * x -x - * e + e - * 1. reduce x to non-negative by tanh(-x) = -tanh(x). - * 2. 0 <= x <= 2**-55 : tanh(x) := x*(one+x) - * -t - * 2**-55 < x <= 1 : tanh(x) := -----; t = expm1(-2x) - * t + 2 - * 2 - * 1 <= x <= 22.0 : tanh(x) := 1- ----- ; t=expm1(2x) - * t + 2 - * 22.0 < x <= INF : tanh(x) := 1. - * - * Special cases: - * tanh(NaN) is NaN; - * only tanh(0)=0 is exact for finite argument. - */ - -#include <float.h> -#include <math.h> -#include <math_private.h> - -static const double one = 1.0, two = 2.0, tiny = 1.0e-300; - -double -__tanh (double x) -{ - double t, z; - int32_t jx, ix, lx; - - /* High word of |x|. */ - EXTRACT_WORDS (jx, lx, x); - ix = jx & 0x7fffffff; - - /* x is INF or NaN */ - if (ix >= 0x7ff00000) - { - if (jx >= 0) - return one / x + one; /* tanh(+-inf)=+-1 */ - else - return one / x - one; /* tanh(NaN) = NaN */ - } - - /* |x| < 22 */ - if (ix < 0x40360000) /* |x|<22 */ - { - if ((ix | lx) == 0) - return x; /* x == +-0 */ - if (ix < 0x3c800000) /* |x|<2**-55 */ - { - math_check_force_underflow (x); - return x * (one + x); /* tanh(small) = small */ - } - if (ix >= 0x3ff00000) /* |x|>=1 */ - { - t = __expm1 (two * fabs (x)); - z = one - two / (t + two); - } - else - { - t = __expm1 (-two * fabs (x)); - z = -t / (t + two); - } - /* |x| > 22, return +-1 */ - } - else - { - z = one - tiny; /* raised inexact flag */ - } - return (jx >= 0) ? z : -z; -} -weak_alias (__tanh, tanh) -#ifdef NO_LONG_DOUBLE -strong_alias (__tanh, __tanhl) -weak_alias (__tanh, tanhl) -#endif |