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           if (__builtin_expect (rcls != FP_SUBNORMAL, 1))
  46             {
  47               __sincos (__real__ x, &sinix, &cosix);
  48             }
  49           else
  50             {
  51               sinix = __real__ x;
  52               cosix = 1.0;
  53             }
  54
  55           if (fabs (__imag__ x) > t)
  56             {
  57               double exp_t = __ieee754_exp (t);
  58               double ix = fabs (__imag__ x);
  59               if (signbit (__imag__ x))
  60                 cosix = -cosix;
  61               ix -= t;
  62               sinix *= exp_t / 2.0;
  63               cosix *= exp_t / 2.0;
  64               if (ix > t)
  65                 {
  66                   ix -= t;
  67                   sinix *= exp_t;
  68                   cosix *= exp_t;
  69                 }
  70               if (ix > t)
  71                 {
  72                   /* Overflow (original imaginary part of x > 3t).  */
  73                   __real__ retval = DBL_MAX * sinix;
  74                   __imag__ retval = DBL_MAX * cosix;
  75                 }
  76               else
  77                 {
  78                   double exp_val = __ieee754_exp (ix);
  79                   __real__ retval = exp_val * sinix;
  80                   __imag__ retval = exp_val * cosix;
  81                 }
  82             }
  83           else
  84             {
  85               __real__ retval = __ieee754_cosh (__imag__ x) * sinix;
  86               __imag__ retval = __ieee754_sinh (__imag__ x) * cosix;
  87             }
  88
  89           if (negate)
  90             __real__ retval = -__real__ retval;
  91         }
  92       else
  93         {
  94           if (icls == FP_ZERO)
  95             {
  96               /* Imaginary part is 0.0.  */
  97               __real__ retval = __nan ("");
  98               __imag__ retval = __imag__ x;
  99
 100               if (rcls == FP_INFINITE)
 101                 feraiseexcept (FE_INVALID);
 102             }
 103           else
 104             {
 105               __real__ retval = __nan ("");
 106               __imag__ retval = __nan ("");
 107
 108               feraiseexcept (FE_INVALID);
 109             }
 110         }
 111     }
 112   else if (icls == FP_INFINITE)
 113     {
 114       /* Imaginary part is infinite.  */
 115       if (rcls == FP_ZERO)
 116         {
 117           /* Real part is 0.0.  */
 118           __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
 119           __imag__ retval = __imag__ x;
 120         }
 121       else if (rcls > FP_ZERO)
 122         {
 123           /* Real part is finite.  */
 124           double sinix, cosix;
 125
 126           if (__builtin_expect (rcls != FP_SUBNORMAL, 1))
 127             {
 128               __sincos (__real__ x, &sinix, &cosix);
 129             }
 130           else
 131             {
 132               sinix = __real__ x;
 133               cosix = 1.0;
 134             }
 135
 136           __real__ retval = __copysign (HUGE_VAL, sinix);
 137           __imag__ retval = __copysign (HUGE_VAL, cosix);
 138
 139           if (negate)
 140             __real__ retval = -__real__ retval;
 141           if (signbit (__imag__ x))
 142             __imag__ retval = -__imag__ retval;
 143         }
 144       else
 145         {
 146           /* The addition raises the invalid exception.  */
 147           __real__ retval = __nan ("");
 148           __imag__ retval = HUGE_VAL;
 149
 150           if (rcls == FP_INFINITE)
 151             feraiseexcept (FE_INVALID);
 152         }
 153     }
 154   else
 155     {
 156       if (rcls == FP_ZERO)
 157         __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
 158       else
 159         __real__ retval = __nan ("");
 160       __imag__ retval = __nan ("");
 161     }
 162
 163   return retval;
 164 }
 165 weak_alias (__csin, csin)
 166 #ifdef NO_LONG_DOUBLE
 167 strong_alias (__csin, __csinl)
 168 weak_alias (__csin, csinl)
 169 #endif