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Diffstat (limited to 'newlib/libm/math/s_tanh.c')
-rw-r--r-- | newlib/libm/math/s_tanh.c | 128 |
1 files changed, 0 insertions, 128 deletions
diff --git a/newlib/libm/math/s_tanh.c b/newlib/libm/math/s_tanh.c deleted file mode 100644 index b5541d0..0000000 --- a/newlib/libm/math/s_tanh.c +++ /dev/null @@ -1,128 +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. - * ==================================================== - */ - -/* - -FUNCTION - <<tanh>>, <<tanhf>>---hyperbolic tangent - -INDEX -tanh -INDEX -tanhf - -ANSI_SYNOPSIS - #include <math.h> - double tanh(double <[x]>); - float tanhf(float <[x]>); - -TRAD_SYNOPSIS - #include <math.h> - double tanh(<[x]>) - double <[x]>; - - float tanhf(<[x]>) - float <[x]>; - - -DESCRIPTION - -<<tanh>> computes the hyperbolic tangent of -the argument <[x]>. Angles are specified in radians. - -<<tanh(<[x]>)>> is defined as -. sinh(<[x]>)/cosh(<[x]>) - -<<tanhf>> is identical, save that it takes and returns <<float>> values. - -RETURNS -The hyperbolic tangent of <[x]> is returned. - -PORTABILITY -<<tanh>> is ANSI C. <<tanhf>> is an extension. - -*/ - -/* 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 "fdlibm.h" - -#ifndef _DOUBLE_IS_32BITS - -#ifdef __STDC__ -static const double one=1.0, two=2.0, tiny = 1.0e-300; -#else -static double one=1.0, two=2.0, tiny = 1.0e-300; -#endif - -#ifdef __STDC__ - double tanh(double x) -#else - double tanh(x) - double x; -#endif -{ - double t,z; - __int32_t jx,ix; - - /* High word of |x|. */ - GET_HIGH_WORD(jx,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<0x3c800000) /* |x|<2**-55 */ - 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; -} - -#endif /* _DOUBLE_IS_32BITS */ |