math/s_csin.c

   1 /* Complex sine function for double.
   2    Copyright (C) 1997-2015 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <complex.h>
  21 #include <fenv.h>
  22 #include <math.h>
  23 #include <math_private.h>
  24 #include <float.h>
  25
  26 __complex__ double
  27 __csin (__complex__ double x)
  28 {
  29   __complex__ double retval;
  30   int negate = signbit (__real__ x);
  31   int rcls = fpclassify (__real__ x);
  32   int icls = fpclassify (__imag__ x);
  33
  34   __real__ x = fabs (__real__ x);
  35
  36   if (__glibc_likely (icls >= FP_ZERO))
  37     {
  38       /* Imaginary part is finite.  */
  39       if (__glibc_likely (rcls >= FP_ZERO))
  40         {
  41           /* Real part is finite.  */
  42           const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2);
  43           double sinix, cosix;
  44
  45           if (__glibc_likely (__real__ x > DBL_MIN))
  46             {
  47               __sincos (__real__ x, &sinix, &cosix);
  48             }
  49           else
  50             {
  51               sinix = __real__ x;
  52               cosix = 1.0;
  53             }
  54
  55           if (negate)
  56             sinix = -sinix;
  57
  58           if (fabs (__imag__ x) > t)
  59             {
  60               double exp_t = __ieee754_exp (t);
  61               double ix = fabs (__imag__ x);
  62               if (signbit (__imag__ x))
  63                 cosix = -cosix;
  64               ix -= t;
  65               sinix *= exp_t / 2.0;
  66               cosix *= exp_t / 2.0;
  67               if (ix > t)
  68                 {
  69                   ix -= t;
  70                   sinix *= exp_t;
  71                   cosix *= exp_t;
  72                 }
  73               if (ix > t)
  74                 {
  75                   /* Overflow (original imaginary part of x > 3t).  */
  76                   __real__ retval = DBL_MAX * sinix;
  77                   __imag__ retval = DBL_MAX * cosix;
  78                 }
  79               else
  80                 {
  81                   double exp_val = __ieee754_exp (ix);
  82                   __real__ retval = exp_val * sinix;
  83                   __imag__ retval = exp_val * cosix;
  84                 }
  85             }
  86           else
  87             {
  88               __real__ retval = __ieee754_cosh (__imag__ x) * sinix;
  89               __imag__ retval = __ieee754_sinh (__imag__ x) * cosix;
  90             }
  91
  92           math_check_force_underflow_complex (retval);
  93         }
  94       else
  95         {
  96           if (icls == FP_ZERO)
  97             {
  98               /* Imaginary part is 0.0.  */
  99               __real__ retval = __nan ("");
 100               __imag__ retval = __imag__ x;
 101
 102               if (rcls == FP_INFINITE)
 103                 feraiseexcept (FE_INVALID);
 104             }
 105           else
 106             {
 107               __real__ retval = __nan ("");
 108               __imag__ retval = __nan ("");
 109
 110               feraiseexcept (FE_INVALID);
 111             }
 112         }
 113     }
 114   else if (icls == FP_INFINITE)
 115     {
 116       /* Imaginary part is infinite.  */
 117       if (rcls == FP_ZERO)
 118         {
 119           /* Real part is 0.0.  */
 120           __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
 121           __imag__ retval = __imag__ x;
 122         }
 123       else if (rcls > FP_ZERO)
 124         {
 125           /* Real part is finite.  */
 126           double sinix, cosix;
 127
 128           if (__glibc_likely (__real__ x > DBL_MIN))
 129             {
 130               __sincos (__real__ x, &sinix, &cosix);
 131             }
 132           else
 133             {
 134               sinix = __real__ x;
 135               cosix = 1.0;
 136             }
 137
 138           __real__ retval = __copysign (HUGE_VAL, sinix);
 139           __imag__ retval = __copysign (HUGE_VAL, cosix);
 140
 141           if (negate)
 142             __real__ retval = -__real__ retval;
 143           if (signbit (__imag__ x))
 144             __imag__ retval = -__imag__ retval;
 145         }
 146       else
 147         {
 148           /* The addition raises the invalid exception.  */
 149           __real__ retval = __nan ("");
 150           __imag__ retval = HUGE_VAL;
 151
 152           if (rcls == FP_INFINITE)
 153             feraiseexcept (FE_INVALID);
 154         }
 155     }
 156   else
 157     {
 158       if (rcls == FP_ZERO)
 159         __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
 160       else
 161         __real__ retval = __nan ("");
 162       __imag__ retval = __nan ("");
 163     }
 164
 165   return retval;
 166 }
 167 weak_alias (__csin, csin)
 168 #ifdef NO_LONG_DOUBLE
 169 strong_alias (__csin, __csinl)
 170 weak_alias (__csin, csinl)
 171 #endif