1 /* Compute complex base 10 logarithm. 2 Copyright (C) 1997, 1998 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, write to the Free 18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 19 02111-1307 USA. */ 20 21 #include <complex.h> 22 #include <math.h> 23 24 #include "math_private.h" 25 26 27 __complex__ long double 28 __clog10l (__complex__ long double x) 29 { 30 __complex__ long double result; 31 int rcls = fpclassify (__real__ x); 32 int icls = fpclassify (__imag__ x); 33 34 if (rcls == FP_ZERO && icls == FP_ZERO) 35 { 36 /* Real and imaginary part are 0.0. */ 37 __imag__ result = signbit (__real__ x) ? M_PIl : 0.0; 38 __imag__ result = copysignl (__imag__ result, __imag__ x); 39 /* Yes, the following line raises an exception. */ 40 __real__ result = -1.0 / fabsl (__real__ x); 41 } 42 else if (rcls != FP_NAN && icls != FP_NAN) 43 { 44 /* Neither real nor imaginary part is NaN. */ 45 __real__ result = log10l (hypotl (__real__ x, 46 __imag__ x)); 47 __imag__ result = M_LOG10El * atan2l (__imag__ x, __real__ x); 48 } 49 else 50 { 51 __imag__ result = nanl (""); 52 if (rcls == FP_INFINITE || icls == FP_INFINITE) 53 /* Real or imaginary part is infinite. */ 54 __real__ result = HUGE_VALL; 55 else 56 __real__ result = nanl (""); 57 } 58 59 return result; 60 } 61 weak_alias (__clog10l, clog10l) 62