From f6d3a72eca7558e3c52cecc8484665399eeea626 Mon Sep 17 00:00:00 2001 From: "Paul E. Murphy" Date: Fri, 1 Jul 2016 11:00:21 -0500 Subject: Prepare to convert _Complex tangent functions This patch has no function changes, except to ensure the git history correctly tracks the changes to convert the double version of these functions into a templated version. --- math/s_ctanh_template.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 math/s_ctanh_template.c (limited to 'math/s_ctanh_template.c') diff --git a/math/s_ctanh_template.c b/math/s_ctanh_template.c new file mode 100644 index 0000000..2d18875 --- /dev/null +++ b/math/s_ctanh_template.c @@ -0,0 +1,129 @@ +/* Complex hyperbole tangent for double. + Copyright (C) 1997-2016 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper , 1997. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include + +__complex__ double +__ctanh (__complex__ double x) +{ + __complex__ double res; + + if (__glibc_unlikely (!isfinite (__real__ x) || !isfinite (__imag__ x))) + { + if (isinf (__real__ x)) + { + __real__ res = __copysign (1.0, __real__ x); + if (isfinite (__imag__ x) && fabs (__imag__ x) > 1.0) + { + double sinix, cosix; + __sincos (__imag__ x, &sinix, &cosix); + __imag__ res = __copysign (0.0, sinix * cosix); + } + else + __imag__ res = __copysign (0.0, __imag__ x); + } + else if (__imag__ x == 0.0) + { + res = x; + } + else + { + __real__ res = __nan (""); + __imag__ res = __nan (""); + + if (isinf (__imag__ x)) + feraiseexcept (FE_INVALID); + } + } + else + { + double sinix, cosix; + double den; + const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2 / 2); + + /* tanh(x+iy) = (sinh(2x) + i*sin(2y))/(cosh(2x) + cos(2y)) + = (sinh(x)*cosh(x) + i*sin(y)*cos(y))/(sinh(x)^2 + cos(y)^2). */ + + if (__glibc_likely (fabs (__imag__ x) > DBL_MIN)) + { + __sincos (__imag__ x, &sinix, &cosix); + } + else + { + sinix = __imag__ x; + cosix = 1.0; + } + + if (fabs (__real__ x) > t) + { + /* Avoid intermediate overflow when the imaginary part of + the result may be subnormal. Ignoring negligible terms, + the real part is +/- 1, the imaginary part is + sin(y)*cos(y)/sinh(x)^2 = 4*sin(y)*cos(y)/exp(2x). */ + double exp_2t = __ieee754_exp (2 * t); + + __real__ res = __copysign (1.0, __real__ x); + __imag__ res = 4 * sinix * cosix; + __real__ x = fabs (__real__ x); + __real__ x -= t; + __imag__ res /= exp_2t; + if (__real__ x > t) + { + /* Underflow (original real part of x has absolute value + > 2t). */ + __imag__ res /= exp_2t; + } + else + __imag__ res /= __ieee754_exp (2 * __real__ x); + } + else + { + double sinhrx, coshrx; + if (fabs (__real__ x) > DBL_MIN) + { + sinhrx = __ieee754_sinh (__real__ x); + coshrx = __ieee754_cosh (__real__ x); + } + else + { + sinhrx = __real__ x; + coshrx = 1.0; + } + + if (fabs (sinhrx) > fabs (cosix) * DBL_EPSILON) + den = sinhrx * sinhrx + cosix * cosix; + else + den = cosix * cosix; + __real__ res = sinhrx * coshrx / den; + __imag__ res = sinix * cosix / den; + } + math_check_force_underflow_complex (res); + } + + return res; +} +weak_alias (__ctanh, ctanh) +#ifdef NO_LONG_DOUBLE +strong_alias (__ctanh, __ctanhl) +weak_alias (__ctanh, ctanhl) +#endif -- cgit v1.1