glibc/math/s_csin.c

183 lines
4.3 KiB
C

/* Complex sine function for double.
Copyright (C) 1997-2015 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
__csin (__complex__ double x)
{
__complex__ double retval;
int negate = signbit (__real__ x);
int rcls = fpclassify (__real__ x);
int icls = fpclassify (__imag__ x);
__real__ x = fabs (__real__ x);
if (__glibc_likely (icls >= FP_ZERO))
{
/* Imaginary part is finite. */
if (__glibc_likely (rcls >= FP_ZERO))
{
/* Real part is finite. */
const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2);
double sinix, cosix;
if (__glibc_likely (rcls != FP_SUBNORMAL))
{
__sincos (__real__ x, &sinix, &cosix);
}
else
{
sinix = __real__ x;
cosix = 1.0;
}
if (fabs (__imag__ x) > t)
{
double exp_t = __ieee754_exp (t);
double ix = fabs (__imag__ x);
if (signbit (__imag__ x))
cosix = -cosix;
ix -= t;
sinix *= exp_t / 2.0;
cosix *= exp_t / 2.0;
if (ix > t)
{
ix -= t;
sinix *= exp_t;
cosix *= exp_t;
}
if (ix > t)
{
/* Overflow (original imaginary part of x > 3t). */
__real__ retval = DBL_MAX * sinix;
__imag__ retval = DBL_MAX * cosix;
}
else
{
double exp_val = __ieee754_exp (ix);
__real__ retval = exp_val * sinix;
__imag__ retval = exp_val * cosix;
}
}
else
{
__real__ retval = __ieee754_cosh (__imag__ x) * sinix;
__imag__ retval = __ieee754_sinh (__imag__ x) * cosix;
}
if (negate)
__real__ retval = -__real__ retval;
if (fabs (__real__ retval) < DBL_MIN)
{
volatile double force_underflow
= __real__ retval * __real__ retval;
(void) force_underflow;
}
if (fabs (__imag__ retval) < DBL_MIN)
{
volatile double force_underflow
= __imag__ retval * __imag__ retval;
(void) force_underflow;
}
}
else
{
if (icls == FP_ZERO)
{
/* Imaginary part is 0.0. */
__real__ retval = __nan ("");
__imag__ retval = __imag__ x;
if (rcls == FP_INFINITE)
feraiseexcept (FE_INVALID);
}
else
{
__real__ retval = __nan ("");
__imag__ retval = __nan ("");
feraiseexcept (FE_INVALID);
}
}
}
else if (icls == FP_INFINITE)
{
/* Imaginary part is infinite. */
if (rcls == FP_ZERO)
{
/* Real part is 0.0. */
__real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
__imag__ retval = __imag__ x;
}
else if (rcls > FP_ZERO)
{
/* Real part is finite. */
double sinix, cosix;
if (__glibc_likely (rcls != FP_SUBNORMAL))
{
__sincos (__real__ x, &sinix, &cosix);
}
else
{
sinix = __real__ x;
cosix = 1.0;
}
__real__ retval = __copysign (HUGE_VAL, sinix);
__imag__ retval = __copysign (HUGE_VAL, cosix);
if (negate)
__real__ retval = -__real__ retval;
if (signbit (__imag__ x))
__imag__ retval = -__imag__ retval;
}
else
{
/* The addition raises the invalid exception. */
__real__ retval = __nan ("");
__imag__ retval = HUGE_VAL;
if (rcls == FP_INFINITE)
feraiseexcept (FE_INVALID);
}
}
else
{
if (rcls == FP_ZERO)
__real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
else
__real__ retval = __nan ("");
__imag__ retval = __nan ("");
}
return retval;
}
weak_alias (__csin, csin)
#ifdef NO_LONG_DOUBLE
strong_alias (__csin, __csinl)
weak_alias (__csin, csinl)
#endif