libquadmath/math/cexpq.c

   1 /* Return value of complex exponential function for complex __float128 value.
   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 cexpq (__complex128 x)
  29 {
  30   __complex128 retval;
  31   int rcls = fpclassifyq (__real__ x);
  32   int icls = fpclassifyq (__imag__ x);
  33
  34   if (__builtin_expect (rcls >= QUADFP_ZERO, 1))
  35     {
  36       /* Real part is finite.  */
  37       if (__builtin_expect (icls >= QUADFP_ZERO, 1))
  38         {
  39           /* Imaginary part is finite.  */
  40           const int t = (int) ((FLT128_MAX_EXP - 1) * M_LN2q);
  41           __float128 sinix, cosix;
  42
  43           if (__builtin_expect (icls != QUADFP_SUBNORMAL, 1))
  44             {
  45               sincosq (__imag__ x, &sinix, &cosix);
  46             }
  47           else
  48             {
  49               sinix = __imag__ x;
  50               cosix = 1.0Q;
  51             }
  52
  53           if (__real__ x > t)
  54             {
  55               __float128 exp_t = expq (t);
  56               __real__ x -= t;
  57               sinix *= exp_t;
  58               cosix *= exp_t;
  59               if (__real__ x > t)
  60                 {
  61                   __real__ x -= t;
  62                   sinix *= exp_t;
  63                   cosix *= exp_t;
  64                 }
  65             }
  66           if (__real__ x > t)
  67             {
  68               /* Overflow (original real part of x > 3t).  */
  69               __real__ retval = FLT128_MAX * cosix;
  70               __imag__ retval = FLT128_MAX * sinix;
  71             }
  72           else
  73             {
  74               __float128 exp_val = expq (__real__ x);
  75               __real__ retval = exp_val * cosix;
  76               __imag__ retval = exp_val * sinix;
  77             }
  78         }
  79       else
  80         {
  81           /* If the imaginary part is +-inf or NaN and the real part
  82              is not +-inf the result is NaN + iNaN.  */
  83           __real__ retval = nanq ("");
  84           __imag__ retval = nanq ("");
  85
  86 #ifdef HAVE_FENV_H
  87           feraiseexcept (FE_INVALID);
  88 #endif
  89         }
  90     }
  91   else if (__builtin_expect (rcls == QUADFP_INFINITE, 1))
  92     {
  93       /* Real part is infinite.  */
  94       if (__builtin_expect (icls >= QUADFP_ZERO, 1))
  95         {
  96           /* Imaginary part is finite.  */
  97           __float128 value = signbitq (__real__ x) ? 0.0Q : HUGE_VALQ;
  98
  99           if (icls == QUADFP_ZERO)
 100             {
 101               /* Imaginary part is 0.0.  */
 102               __real__ retval = value;
 103               __imag__ retval = __imag__ x;
 104             }
 105           else
 106             {
 107               __float128 sinix, cosix;
 108
 109               if (__builtin_expect (icls != QUADFP_SUBNORMAL, 1))
 110                 {
 111                   sincosq (__imag__ x, &sinix, &cosix);
 112                 }
 113               else
 114                 {
 115                   sinix = __imag__ x;
 116                   cosix = 1.0Q;
 117                 }
 118
 119               __real__ retval = copysignq (value, cosix);
 120               __imag__ retval = copysignq (value, sinix);
 121             }
 122         }
 123       else if (signbitq (__real__ x) == 0)
 124         {
 125           __real__ retval = HUGE_VALQ;
 126           __imag__ retval = nanq ("");
 127
 128 #ifdef HAVE_FENV_H
 129           if (icls == QUADFP_INFINITE)
 130             feraiseexcept (FE_INVALID);
 131 #endif
 132         }
 133       else
 134         {
 135           __real__ retval = 0.0Q;
 136           __imag__ retval = copysignq (0.0Q, __imag__ x);
 137         }
 138     }
 139   else
 140     {
 141       /* If the real part is NaN the result is NaN + iNaN.  */
 142       __real__ retval = nanq ("");
 143       __imag__ retval = nanq ("");
 144
 145 #ifdef HAVE_FENV_H
 146       if (rcls != QUADFP_NAN || icls != QUADFP_NAN)
 147         feraiseexcept (FE_INVALID);
 148 #endif
 149     }
 150
 151   return retval;
 152 }