libquadmath/math/csinq.c

   1 /* Complex sine function for complex __float128.
   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 "quadmath-imp.h"
  21
  22 #ifdef HAVE_FENV_H
  23 # include <fenv.h>
  24 #endif
  25
  26
  27 __complex128
  28 csinq (__complex128 x)
  29 {
  30   __complex128 retval;
  31   int negate = signbitq (__real__ x);
  32   int rcls = fpclassifyq (__real__ x);
  33   int icls = fpclassifyq (__imag__ x);
  34
  35   __real__ x = fabsq (__real__ x);
  36
  37   if (__builtin_expect (icls >= QUADFP_ZERO, 1))
  38     {
  39       /* Imaginary part is finite.  */
  40       if (__builtin_expect (rcls >= QUADFP_ZERO, 1))
  41         {
  42           /* Real part is finite.  */
  43           const int t = (int) ((FLT128_MAX_EXP - 1) * M_LN2q);
  44           __float128 sinix, cosix;
  45
  46           if (__builtin_expect (rcls != QUADFP_SUBNORMAL, 1))
  47             {
  48               sincosq (__real__ x, &sinix, &cosix);
  49             }
  50           else
  51             {
  52               sinix = __real__ x;
  53               cosix = 1.0Q;
  54             }
  55
  56           if (fabsq (__imag__ x) > t)
  57             {
  58               __float128 exp_t = expq (t);
  59               __float128 ix = fabsq (__imag__ x);
  60               if (signbitq (__imag__ x))
  61                 cosix = -cosix;
  62               ix -= t;
  63               sinix *= exp_t / 2.0Q;
  64               cosix *= exp_t / 2.0Q;
  65               if (ix > t)
  66                 {
  67                   ix -= t;
  68                   sinix *= exp_t;
  69                   cosix *= exp_t;
  70                 }
  71               if (ix > t)
  72                 {
  73                   /* Overflow (original imaginary part of x > 3t).  */
  74                   __real__ retval = FLT128_MAX * sinix;
  75                   __imag__ retval = FLT128_MAX * cosix;
  76                 }
  77               else
  78                 {
  79                   __float128 exp_val = expq (ix);
  80                   __real__ retval = exp_val * sinix;
  81                   __imag__ retval = exp_val * cosix;
  82                 }
  83             }
  84           else
  85             {
  86               __real__ retval = coshq (__imag__ x) * sinix;
  87               __imag__ retval = sinhq (__imag__ x) * cosix;
  88             }
  89
  90           if (negate)
  91             __real__ retval = -__real__ retval;
  92         }
  93       else
  94         {
  95           if (icls == QUADFP_ZERO)
  96             {
  97               /* Imaginary part is 0.0.  */
  98               __real__ retval = nanq ("");
  99               __imag__ retval = __imag__ x;
 100
 101 #ifdef HAVE_FENV_H
 102               if (rcls == QUADFP_INFINITE)
 103                 feraiseexcept (FE_INVALID);
 104 #endif
 105             }
 106           else
 107             {
 108               __real__ retval = nanq ("");
 109               __imag__ retval = nanq ("");
 110
 111 #ifdef HAVE_FENV_H
 112               feraiseexcept (FE_INVALID);
 113 #endif
 114             }
 115         }
 116     }
 117   else if (icls == QUADFP_INFINITE)
 118     {
 119       /* Imaginary part is infinite.  */
 120       if (rcls == QUADFP_ZERO)
 121         {
 122           /* Real part is 0.0.  */
 123           __real__ retval = copysignq (0.0Q, negate ? -1.0Q : 1.0Q);
 124           __imag__ retval = __imag__ x;
 125         }
 126       else if (rcls > QUADFP_ZERO)
 127         {
 128           /* Real part is finite.  */
 129           __float128 sinix, cosix;
 130
 131           if (__builtin_expect (rcls != QUADFP_SUBNORMAL, 1))
 132             {
 133               sincosq (__real__ x, &sinix, &cosix);
 134             }
 135           else
 136             {
 137               sinix = __real__ x;
 138               cosix = 1.0;
 139             }
 140
 141           __real__ retval = copysignq (HUGE_VALQ, sinix);
 142           __imag__ retval = copysignq (HUGE_VALQ, cosix);
 143
 144           if (negate)
 145             __real__ retval = -__real__ retval;
 146           if (signbitq (__imag__ x))
 147             __imag__ retval = -__imag__ retval;
 148         }
 149       else
 150         {
 151           /* The addition raises the invalid exception.  */
 152           __real__ retval = nanq ("");
 153           __imag__ retval = HUGE_VALQ;
 154
 155 #ifdef HAVE_FENV_H
 156           if (rcls == QUADFP_INFINITE)
 157             feraiseexcept (FE_INVALID);
 158 #endif
 159         }
 160     }
 161   else
 162     {
 163       if (rcls == QUADFP_ZERO)
 164         __real__ retval = copysignq (0.0Q, negate ? -1.0Q : 1.0Q);
 165       else
 166         __real__ retval = nanq ("");
 167       __imag__ retval = nanq ("");
 168     }
 169
 170   return retval;
 171 }