math/s_csin.c

   1 /* Complex sine function for double.
   2    Copyright (C) 1997 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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <complex.h>
  22 #include <fenv.h>
  23 #include <math.h>
  24
  25 #include "math_private.h"
  26
  27
  28 __complex__ double
  29 __csin (__complex__ double x)
  30 {
  31   __complex__ double retval;
  32   int negate = signbit (__real__ x);
  33   int rcls = fpclassify (__real__ x);
  34   int icls = fpclassify (__imag__ x);
  35
  36   __real__ x = fabs (__real__ x);
  37
  38   if (icls >= FP_ZERO)
  39     {
  40       /* Imaginary part is finite.  */
  41       if (rcls >= FP_ZERO)
  42         {
  43           /* Real part is finite.  */
  44           double sinh_val = __ieee754_sinh (__imag__ x);
  45           double cosh_val = __ieee754_cosh (__imag__ x);
  46           double sinix, cosix;
  47
  48           __sincos (__real__ x, &sinix, &cosix);
  49
  50           __real__ retval = cosh_val * sinix;
  51           __imag__ retval = sinh_val * cosix;
  52
  53           if (negate)
  54             __real__ retval = -__real__ retval;
  55         }
  56       else
  57         {
  58           if (icls == FP_ZERO)
  59             {
  60               /* Imaginary part is 0.0.  */
  61               __real__ retval = __nan ("");
  62               __imag__ retval = __imag__ x;
  63
  64 #ifdef FE_INVALID
  65               if (rcls == FP_INFINITE)
  66                 feraiseexcept (FE_INVALID);
  67 #endif
  68             }
  69           else
  70             {
  71               __real__ retval = __nan ("");
  72               __imag__ retval = __nan ("");
  73
  74 #ifdef FE_INVALID
  75               feraiseexcept (FE_INVALID);
  76 #endif
  77             }
  78         }
  79     }
  80   else if (icls == FP_INFINITE)
  81     {
  82       /* Imaginary part is infinite.  */
  83       if (rcls == FP_ZERO)
  84         {
  85           /* Real part is 0.0.  */
  86           __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
  87           __imag__ retval = __imag__ x;
  88         }
  89       else if (rcls > FP_ZERO)
  90         {
  91           /* Real part is finite.  */
  92           double sinix, cosix;
  93
  94           __sincos (__real__ x, &sinix, &cosix);
  95
  96           __real__ retval = __copysign (HUGE_VAL, sinix);
  97           __imag__ retval = __copysign (HUGE_VAL, cosix);
  98
  99           if (negate)
 100             __real__ retval = -__real__ retval;
 101           if (signbit (__imag__ x))
 102             __imag__ retval = -__imag__ retval;
 103         }
 104       else
 105         {
 106           /* The addition raises the invalid exception.  */
 107           __real__ retval = __nan ("");
 108           __imag__ retval = HUGE_VAL;
 109
 110 #ifdef FE_INVALID
 111           if (rcls == FP_INFINITE)
 112             feraiseexcept (FE_INVALID);
 113 #endif
 114         }
 115     }
 116   else
 117     {
 118       if (rcls == FP_ZERO)
 119         __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
 120       else
 121         __real__ retval = __nan ("");
 122       __imag__ retval = __nan ("");
 123     }
 124
 125   return retval;
 126 }
 127 weak_alias (__csin, csin)
 128 #ifdef NO_LONG_DOUBLE
 129 strong_alias (__csin, __csinl)
 130 weak_alias (__csin, csinl)
 131 #endif