109 lines
2.9 KiB
C
109 lines
2.9 KiB
C
/* Return arc hyperbole cosine for float value.
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Copyright (C) 1997, 2006 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <complex.h>
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#include <math.h>
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#include <math_private.h>
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__complex__ float
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__cacoshf (__complex__ float x)
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{
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__complex__ float res;
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int rcls = fpclassify (__real__ x);
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int icls = fpclassify (__imag__ x);
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if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
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{
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if (icls == FP_INFINITE)
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{
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__real__ res = HUGE_VALF;
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if (rcls == FP_NAN)
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__imag__ res = __nanf ("");
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else
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__imag__ res = __copysignf ((rcls == FP_INFINITE
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? (__real__ x < 0.0
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? M_PI - M_PI_4 : M_PI_4)
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: M_PI_2), __imag__ x);
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}
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else if (rcls == FP_INFINITE)
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{
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__real__ res = HUGE_VALF;
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if (icls >= FP_ZERO)
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__imag__ res = __copysignf (signbit (__real__ x) ? M_PI : 0.0,
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__imag__ x);
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else
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__imag__ res = __nanf ("");
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}
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else
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{
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__real__ res = __nanf ("");
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__imag__ res = __nanf ("");
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}
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}
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else if (rcls == FP_ZERO && icls == FP_ZERO)
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{
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__real__ res = 0.0;
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__imag__ res = __copysignf (M_PI_2, __imag__ x);
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}
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else
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{
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#if 1
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__complex__ float y;
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__real__ y = (__real__ x - __imag__ x) * (__real__ x + __imag__ x) - 1.0;
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__imag__ y = 2.0 * __real__ x * __imag__ x;
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y = __csqrtf (y);
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if (__real__ x < 0.0)
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y = -y;
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__real__ y += __real__ x;
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__imag__ y += __imag__ x;
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res = __clogf (y);
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#else
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float re2 = __real__ x * __real__ x;
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float im2 = __imag__ x * __imag__ x;
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float sq = re2 - im2 - 1.0;
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float ro = __ieee754_sqrtf (sq * sq + 4 * re2 * im2);
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float a = __ieee754_sqrtf ((sq + ro) / 2.0);
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float b = __ieee754_sqrtf ((-sq + ro) / 2.0);
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__real__ res = 0.5 * __ieee754_logf (re2 + __real__ x * 2 * a
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+ im2 + __imag__ x * 2 * b
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+ ro);
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__imag__ res = __ieee754_atan2f (__imag__ x + b, __real__ x + a);
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#endif
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/* We have to use the positive branch. */
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if (__real__ res < 0.0)
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res = -res;
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}
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return res;
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}
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#ifndef __cacoshf
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weak_alias (__cacoshf, cacoshf)
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#endif
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