math/s_clog10l.c

   1 /* Compute complex base 10 logarithm.
   2    Copyright (C) 1997, 1998, 2011 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 <math.h>
  22 #include <math_private.h>
  23
  24
  25 __complex__ long double
  26 __clog10l (__complex__ long double x)
  27 {
  28   __complex__ long double result;
  29   int rcls = fpclassify (__real__ x);
  30   int icls = fpclassify (__imag__ x);
  31
  32   if (__builtin_expect (rcls == FP_ZERO && icls == FP_ZERO, 0))
  33     {
  34       /* Real and imaginary part are 0.0.  */
  35       __imag__ result = signbit (__real__ x) ? M_PIl : 0.0;
  36       __imag__ result = __copysignl (__imag__ result, __imag__ x);
  37       /* Yes, the following line raises an exception.  */
  38       __real__ result = -1.0 / fabsl (__real__ x);
  39     }
  40   else if (__builtin_expect (rcls != FP_NAN && icls != FP_NAN, 1))
  41     {
  42       /* Neither real nor imaginary part is NaN.  */
  43       __real__ result = __ieee754_log10l (__ieee754_hypotl (__real__ x,
  44                                                             __imag__ x));
  45       __imag__ result = M_LOG10El * __ieee754_atan2l (__imag__ x, __real__ x);
  46     }
  47   else
  48     {
  49       __imag__ result = __nanl ("");
  50       if (rcls == FP_INFINITE || icls == FP_INFINITE)
  51         /* Real or imaginary part is infinite.  */
  52         __real__ result = HUGE_VALL;
  53       else
  54         __real__ result = __nanl ("");
  55     }
  56
  57   return result;
  58 }
  59 weak_alias (__clog10l, clog10l)