math/s_csinl.c

   1 /* Complex sine function for long 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__ long double
  27 __csinl (__complex__ long double x)
  28 {
  29   __complex__ long double retval;
  30   int negate = signbit (__real__ x);
  31   int rcls = fpclassify (__real__ x);
  32   int icls = fpclassify (__imag__ x);
  33
  34   __real__ x = fabsl (__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) ((LDBL_MAX_EXP - 1) * M_LN2l);
  43           long double sinix, cosix;
  44
  45           if (__glibc_likely (__real__ x > LDBL_MIN))
  46             {
  47               __sincosl (__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 (fabsl (__imag__ x) > t)
  59             {
  60               long double exp_t = __ieee754_expl (t);
  61               long double ix = fabsl (__imag__ x);
  62               if (signbit (__imag__ x))
  63                 cosix = -cosix;
  64               ix -= t;
  65               sinix *= exp_t / 2.0L;
  66               cosix *= exp_t / 2.0L;
  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 = LDBL_MAX * sinix;
  77                   __imag__ retval = LDBL_MAX * cosix;
  78                 }
  79               else
  80                 {
  81                   long double exp_val = __ieee754_expl (ix);
  82                   __real__ retval = exp_val * sinix;
  83                   __imag__ retval = exp_val * cosix;
  84                 }
  85             }
  86           else
  87             {
  88               __real__ retval = __ieee754_coshl (__imag__ x) * sinix;
  89               __imag__ retval = __ieee754_sinhl (__imag__ x) * cosix;
  90             }
  91
  92           if (fabsl (__real__ retval) < LDBL_MIN)
  93             {
  94               volatile long double force_underflow
  95                 = __real__ retval * __real__ retval;
  96               (void) force_underflow;
  97             }
  98           if (fabsl (__imag__ retval) < LDBL_MIN)
  99             {
 100               volatile long double force_underflow
 101                 = __imag__ retval * __imag__ retval;
 102               (void) force_underflow;
 103             }
 104         }
 105       else
 106         {
 107           if (icls == FP_ZERO)
 108             {
 109               /* Imaginary part is 0.0.  */
 110               __real__ retval = __nanl ("");
 111               __imag__ retval = __imag__ x;
 112
 113               if (rcls == FP_INFINITE)
 114                 feraiseexcept (FE_INVALID);
 115             }
 116           else
 117             {
 118               __real__ retval = __nanl ("");
 119               __imag__ retval = __nanl ("");
 120
 121               feraiseexcept (FE_INVALID);
 122             }
 123         }
 124     }
 125   else if (icls == FP_INFINITE)
 126     {
 127       /* Imaginary part is infinite.  */
 128       if (rcls == FP_ZERO)
 129         {
 130           /* Real part is 0.0.  */
 131           __real__ retval = __copysignl (0.0, negate ? -1.0 : 1.0);
 132           __imag__ retval = __imag__ x;
 133         }
 134       else if (rcls > FP_ZERO)
 135         {
 136           /* Real part is finite.  */
 137           long double sinix, cosix;
 138
 139           if (__glibc_likely (__real__ x > LDBL_MIN))
 140             {
 141               __sincosl (__real__ x, &sinix, &cosix);
 142             }
 143           else
 144             {
 145               sinix = __real__ x;
 146               cosix = 1.0;
 147             }
 148
 149           __real__ retval = __copysignl (HUGE_VALL, sinix);
 150           __imag__ retval = __copysignl (HUGE_VALL, cosix);
 151
 152           if (negate)
 153             __real__ retval = -__real__ retval;
 154           if (signbit (__imag__ x))
 155             __imag__ retval = -__imag__ retval;
 156         }
 157       else
 158         {
 159           /* The addition raises the invalid exception.  */
 160           __real__ retval = __nanl ("");
 161           __imag__ retval = HUGE_VALL;
 162
 163           if (rcls == FP_INFINITE)
 164             feraiseexcept (FE_INVALID);
 165         }
 166     }
 167   else
 168     {
 169       if (rcls == FP_ZERO)
 170         __real__ retval = __copysignl (0.0, negate ? -1.0 : 1.0);
 171       else
 172         __real__ retval = __nanl ("");
 173       __imag__ retval = __nanl ("");
 174     }
 175
 176   return retval;
 177 }
 178 weak_alias (__csinl, csinl)