| 1 | /* Compute complex base 10 logarithm. |
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| 2 | Copyright (C) 1997, 1998 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
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| 5 | |
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| 6 | The GNU C Library is free software; you can redistribute it and/or |
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| 7 | modify it under the terms of the GNU Lesser General Public |
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| 8 | License as published by the Free Software Foundation; either |
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| 9 | version 2.1 of the License, or (at your option) any later version. |
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| 10 | |
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| 11 | The GNU C Library is distributed in the hope that it will be useful, |
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 14 | Lesser General Public License for more details. |
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| 15 | |
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| 16 | You should have received a copy of the GNU Lesser General Public |
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| 17 | License along with the GNU C Library; if not, write to the Free |
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| 18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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| 19 | 02111-1307 USA. */ |
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| 20 | |
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| 21 | #include <complex.h> |
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| 22 | #include <math.h> |
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| 23 | |
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| 24 | #include "math_private.h" |
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| 25 | |
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| 26 | |
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| 27 | __complex__ long double |
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| 28 | __clog10l (__complex__ long double x) |
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| 29 | { |
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| 30 | __complex__ long double result; |
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| 31 | int rcls = fpclassify (__real__ x); |
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| 32 | int icls = fpclassify (__imag__ x); |
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| 33 | |
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| 34 | if (rcls == FP_ZERO && icls == FP_ZERO) |
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| 35 | { |
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| 36 | /* Real and imaginary part are 0.0. */ |
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| 37 | __imag__ result = signbit (__real__ x) ? M_PIl : 0.0; |
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| 38 | __imag__ result = __copysignl (__imag__ result, __imag__ x); |
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| 39 | /* Yes, the following line raises an exception. */ |
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| 40 | __real__ result = -1.0 / fabsl (__real__ x); |
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| 41 | } |
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| 42 | else if (rcls != FP_NAN && icls != FP_NAN) |
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| 43 | { |
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| 44 | /* Neither real nor imaginary part is NaN. */ |
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| 45 | __real__ result = __ieee754_log10l (__ieee754_hypotl (__real__ x, |
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| 46 | __imag__ x)); |
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| 47 | __imag__ result = M_LOG10El * __ieee754_atan2l (__imag__ x, __real__ x); |
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| 48 | } |
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| 49 | else |
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| 50 | { |
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| 51 | __imag__ result = __nanl (""); |
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| 52 | if (rcls == FP_INFINITE || icls == FP_INFINITE) |
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| 53 | /* Real or imaginary part is infinite. */ |
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| 54 | __real__ result = HUGE_VALL; |
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| 55 | else |
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| 56 | __real__ result = __nanl (""); |
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| 57 | } |
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| 58 | |
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| 59 | return result; |
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| 60 | } |
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| 61 | weak_alias (__clog10l, clog10l) |
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