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glibc/math/s_cexp.c
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/* Return value of complex exponential function for double complex value. | |
Copyright (C) 1997-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Ulrich Drepper <drepper@cygnus.com>, 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 | |
<http://www.gnu.org/licenses/>. */ | |
#include <complex.h> | |
#include <fenv.h> | |
#include <math.h> | |
#include <math_private.h> | |
#include <float.h> | |
__complex__ double | |
__cexp (__complex__ double x) | |
{ | |
__complex__ double retval; | |
int rcls = fpclassify (__real__ x); | |
int icls = fpclassify (__imag__ x); | |
if (__glibc_likely (rcls >= FP_ZERO)) | |
{ | |
/* Real part is finite. */ | |
if (__glibc_likely (icls >= FP_ZERO)) | |
{ | |
/* Imaginary part is finite. */ | |
const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2); | |
double sinix, cosix; | |
if (__glibc_likely (fabs (__imag__ x) > DBL_MIN)) | |
{ | |
__sincos (__imag__ x, &sinix, &cosix); | |
} | |
else | |
{ | |
sinix = __imag__ x; | |
cosix = 1.0; | |
} | |
if (__real__ x > t) | |
{ | |
double exp_t = __ieee754_exp (t); | |
__real__ x -= t; | |
sinix *= exp_t; | |
cosix *= exp_t; | |
if (__real__ x > t) | |
{ | |
__real__ x -= t; | |
sinix *= exp_t; | |
cosix *= exp_t; | |
} | |
} | |
if (__real__ x > t) | |
{ | |
/* Overflow (original real part of x > 3t). */ | |
__real__ retval = DBL_MAX * cosix; | |
__imag__ retval = DBL_MAX * sinix; | |
} | |
else | |
{ | |
double exp_val = __ieee754_exp (__real__ x); | |
__real__ retval = exp_val * cosix; | |
__imag__ retval = exp_val * sinix; | |
} | |
math_check_force_underflow_complex (retval); | |
} | |
else | |
{ | |
/* If the imaginary part is +-inf or NaN and the real part | |
is not +-inf the result is NaN + iNaN. */ | |
__real__ retval = __nan (""); | |
__imag__ retval = __nan (""); | |
feraiseexcept (FE_INVALID); | |
} | |
} | |
else if (__glibc_likely (rcls == FP_INFINITE)) | |
{ | |
/* Real part is infinite. */ | |
if (__glibc_likely (icls >= FP_ZERO)) | |
{ | |
/* Imaginary part is finite. */ | |
double value = signbit (__real__ x) ? 0.0 : HUGE_VAL; | |
if (icls == FP_ZERO) | |
{ | |
/* Imaginary part is 0.0. */ | |
__real__ retval = value; | |
__imag__ retval = __imag__ x; | |
} | |
else | |
{ | |
double sinix, cosix; | |
if (__glibc_likely (fabs (__imag__ x) > DBL_MIN)) | |
{ | |
__sincos (__imag__ x, &sinix, &cosix); | |
} | |
else | |
{ | |
sinix = __imag__ x; | |
cosix = 1.0; | |
} | |
__real__ retval = __copysign (value, cosix); | |
__imag__ retval = __copysign (value, sinix); | |
} | |
} | |
else if (signbit (__real__ x) == 0) | |
{ | |
__real__ retval = HUGE_VAL; | |
__imag__ retval = __nan (""); | |
if (icls == FP_INFINITE) | |
feraiseexcept (FE_INVALID); | |
} | |
else | |
{ | |
__real__ retval = 0.0; | |
__imag__ retval = __copysign (0.0, __imag__ x); | |
} | |
} | |
else | |
{ | |
/* If the real part is NaN the result is NaN + iNaN unless the | |
imaginary part is zero. */ | |
__real__ retval = __nan (""); | |
if (icls == FP_ZERO) | |
__imag__ retval = __imag__ x; | |
else | |
{ | |
__imag__ retval = __nan (""); | |
if (rcls != FP_NAN || icls != FP_NAN) | |
feraiseexcept (FE_INVALID); | |
} | |
} | |
return retval; | |
} | |
weak_alias (__cexp, cexp) | |
#ifdef NO_LONG_DOUBLE | |
strong_alias (__cexp, __cexpl) | |
weak_alias (__cexp, cexpl) | |
#endif |