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Some of the complex arithmetic functions have the following pattern: in some piece of code, one part of the input (real or imaginary, depending on the function) is either infinite or NaN. Part of the result is to be set to NaN in either case, and FE_INVALID raised only if the relevant part of the input was infinite. In such a case, there is no actual need for the conditional on the type of the input, since subtracting the relevant part of the input from itself will produce a NaN, with FE_INVALID only if the relevant part of the input was infinite. This simplifies the code, and as a quality-of-implementation matter also improves things by propagating NaN payloads. (Right now these functions always raise FE_INVALID for signaling NaN arguments because of the call to fpclassify - at least unless glibc is built with -Os - but if fpclassify moves to using integer arithmetic in future, doing arithmetic on the NaN argument also ensures an exception for sNaNs.) Tested for x86_64 and x86. * math/s_ccosh_template.c (M_DECL_FUNC (__ccosh)): Instead of raising FE_INVALID with feraisexcept in case where part of argument is infinite, subtract that part of argument from itself. * math/s_cexp_template.c (M_DECL_FUNC (__cexp)): Likewise. * math/s_csin_template.c (M_DECL_FUNC (__csin)): Likewise. * math/s_csinh_template.c (M_DECL_FUNC (__csinh)): Likewise.
142 lines
3.4 KiB
C
142 lines
3.4 KiB
C
/* Complex cosine hyperbolic function for float types.
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Copyright (C) 1997-2016 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, see
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<http://www.gnu.org/licenses/>. */
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#include <complex.h>
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#include <fenv.h>
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#include <math.h>
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#include <math_private.h>
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#include <float.h>
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CFLOAT
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M_DECL_FUNC (__ccosh) (CFLOAT x)
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{
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CFLOAT retval;
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int rcls = fpclassify (__real__ x);
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int icls = fpclassify (__imag__ x);
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if (__glibc_likely (rcls >= FP_ZERO))
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{
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/* Real part is finite. */
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if (__glibc_likely (icls >= FP_ZERO))
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{
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/* Imaginary part is finite. */
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const int t = (int) ((M_MAX_EXP - 1) * M_MLIT (M_LN2));
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FLOAT sinix, cosix;
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if (__glibc_likely (M_FABS (__imag__ x) > M_MIN))
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{
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M_SINCOS (__imag__ x, &sinix, &cosix);
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}
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else
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{
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sinix = __imag__ x;
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cosix = 1;
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}
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if (M_FABS (__real__ x) > t)
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{
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FLOAT exp_t = M_EXP (t);
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FLOAT rx = M_FABS (__real__ x);
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if (signbit (__real__ x))
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sinix = -sinix;
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rx -= t;
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sinix *= exp_t / 2;
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cosix *= exp_t / 2;
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if (rx > t)
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{
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rx -= t;
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sinix *= exp_t;
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cosix *= exp_t;
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}
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if (rx > t)
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{
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/* Overflow (original real part of x > 3t). */
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__real__ retval = M_MAX * cosix;
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__imag__ retval = M_MAX * sinix;
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}
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else
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{
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FLOAT exp_val = M_EXP (rx);
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__real__ retval = exp_val * cosix;
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__imag__ retval = exp_val * sinix;
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}
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}
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else
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{
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__real__ retval = M_COSH (__real__ x) * cosix;
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__imag__ retval = M_SINH (__real__ x) * sinix;
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}
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math_check_force_underflow_complex (retval);
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}
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else
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{
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__imag__ retval = __real__ x == 0 ? 0 : M_NAN;
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__real__ retval = __imag__ x - __imag__ x;
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}
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}
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else if (rcls == FP_INFINITE)
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{
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/* Real part is infinite. */
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if (__glibc_likely (icls > FP_ZERO))
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{
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/* Imaginary part is finite. */
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FLOAT sinix, cosix;
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if (__glibc_likely (M_FABS (__imag__ x) > M_MIN))
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{
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M_SINCOS (__imag__ x, &sinix, &cosix);
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}
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else
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{
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sinix = __imag__ x;
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cosix = 1;
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}
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__real__ retval = M_COPYSIGN (M_HUGE_VAL, cosix);
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__imag__ retval = (M_COPYSIGN (M_HUGE_VAL, sinix)
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* M_COPYSIGN (1, __real__ x));
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}
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else if (icls == FP_ZERO)
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{
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/* Imaginary part is 0.0. */
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__real__ retval = M_HUGE_VAL;
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__imag__ retval = __imag__ x * M_COPYSIGN (1, __real__ x);
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}
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else
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{
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__real__ retval = M_HUGE_VAL;
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__imag__ retval = __imag__ x - __imag__ x;
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}
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}
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else
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{
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__real__ retval = M_NAN;
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__imag__ retval = __imag__ x == 0 ? __imag__ x : M_NAN;
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}
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return retval;
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}
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declare_mgen_alias (__ccosh, ccosh);
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#if M_LIBM_NEED_COMPAT (carg)
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declare_mgen_libm_compat (__ccosh, ccosh)
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#endif
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