math/s_csin.c

   1 /* Complex sine function for double.
   2    Copyright (C) 1997-2012 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 (__builtin_expect (icls >= FP_ZERO, 1))
  37     {
  38       /* Imaginary part is finite.  */
  39       if (__builtin_expect (rcls >= FP_ZERO, 1))
  40         {
  41           /* Real part is finite.  */
  42           const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2);
  43           double sinix, cosix;
  44
  45           __sincos (__real__ x, &sinix, &cosix);
  46
  47           if (fabs (__imag__ x) > t)
  48             {
  49               double exp_t = __ieee754_exp (t);
  50               double ix = fabs (__imag__ x);
  51               if (signbit (__imag__ x))
  52                 cosix = -cosix;
  53               ix -= t;
  54               sinix *= exp_t / 2.0;
  55               cosix *= exp_t / 2.0;
  56               if (ix > t)
  57                 {
  58                   ix -= t;
  59                   sinix *= exp_t;
  60                   cosix *= exp_t;
  61                 }
  62               if (ix > t)
  63                 {
  64                   /* Overflow (original imaginary part of x > 3t).  */
  65                   __real__ retval = DBL_MAX * sinix;
  66                   __imag__ retval = DBL_MAX * cosix;
  67                 }
  68               else
  69                 {
  70                   double exp_val = __ieee754_exp (ix);
  71                   __real__ retval = exp_val * sinix;
  72                   __imag__ retval = exp_val * cosix;
  73                 }
  74             }
  75           else
  76             {
  77               __real__ retval = __ieee754_cosh (__imag__ x) * sinix;
  78               __imag__ retval = __ieee754_sinh (__imag__ x) * cosix;
  79             }
  80
  81           if (negate)
  82             __real__ retval = -__real__ retval;
  83         }
  84       else
  85         {
  86           if (icls == FP_ZERO)
  87             {
  88               /* Imaginary part is 0.0.  */
  89               __real__ retval = __nan ("");
  90               __imag__ retval = __imag__ x;
  91
  92               if (rcls == FP_INFINITE)
  93                 feraiseexcept (FE_INVALID);
  94             }
  95           else
  96             {
  97               __real__ retval = __nan ("");
  98               __imag__ retval = __nan ("");
  99
 100               feraiseexcept (FE_INVALID);
 101             }
 102         }
 103     }
 104   else if (icls == FP_INFINITE)
 105     {
 106       /* Imaginary part is infinite.  */
 107       if (rcls == FP_ZERO)
 108         {
 109           /* Real part is 0.0.  */
 110           __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
 111           __imag__ retval = __imag__ x;
 112         }
 113       else if (rcls > FP_ZERO)
 114         {
 115           /* Real part is finite.  */
 116           double sinix, cosix;
 117
 118           __sincos (__real__ x, &sinix, &cosix);
 119
 120           __real__ retval = __copysign (HUGE_VAL, sinix);
 121           __imag__ retval = __copysign (HUGE_VAL, cosix);
 122
 123           if (negate)
 124             __real__ retval = -__real__ retval;
 125           if (signbit (__imag__ x))
 126             __imag__ retval = -__imag__ retval;
 127         }
 128       else
 129         {
 130           /* The addition raises the invalid exception.  */
 131           __real__ retval = __nan ("");
 132           __imag__ retval = HUGE_VAL;
 133
 134           if (rcls == FP_INFINITE)
 135             feraiseexcept (FE_INVALID);
 136         }
 137     }
 138   else
 139     {
 140       if (rcls == FP_ZERO)
 141         __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
 142       else
 143         __real__ retval = __nan ("");
 144       __imag__ retval = __nan ("");
 145     }
 146
 147   return retval;
 148 }
 149 weak_alias (__csin, csin)
 150 #ifdef NO_LONG_DOUBLE
 151 strong_alias (__csin, __csinl)
 152 weak_alias (__csin, csinl)
 153 #endif