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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
116 lines
3.2 KiB
C
116 lines
3.2 KiB
C
/* Compute complex natural logarithm.
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Copyright (C) 1997-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <complex.h>
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#include <math.h>
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#include <math_private.h>
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#include <math-underflow.h>
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#include <float.h>
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CFLOAT
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M_DECL_FUNC (__clog) (CFLOAT x)
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{
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CFLOAT result;
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int rcls = fpclassify (__real__ x);
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int icls = fpclassify (__imag__ x);
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if (__glibc_unlikely (rcls == FP_ZERO && icls == FP_ZERO))
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{
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/* Real and imaginary part are 0.0. */
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__imag__ result = signbit (__real__ x) ? (FLOAT) M_MLIT (M_PI) : 0;
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__imag__ result = M_COPYSIGN (__imag__ result, __imag__ x);
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/* Yes, the following line raises an exception. */
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__real__ result = -1 / M_FABS (__real__ x);
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}
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else if (__glibc_likely (rcls != FP_NAN && icls != FP_NAN))
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{
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/* Neither real nor imaginary part is NaN. */
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FLOAT absx = M_FABS (__real__ x), absy = M_FABS (__imag__ x);
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int scale = 0;
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if (absx < absy)
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{
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FLOAT t = absx;
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absx = absy;
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absy = t;
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}
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if (absx > M_MAX / 2)
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{
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scale = -1;
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absx = M_SCALBN (absx, scale);
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absy = (absy >= M_MIN * 2 ? M_SCALBN (absy, scale) : 0);
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}
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else if (absx < M_MIN && absy < M_MIN)
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{
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scale = M_MANT_DIG;
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absx = M_SCALBN (absx, scale);
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absy = M_SCALBN (absy, scale);
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}
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if (absx == 1 && scale == 0)
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{
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__real__ result = M_LOG1P (absy * absy) / 2;
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math_check_force_underflow_nonneg (__real__ result);
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}
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else if (absx > 1 && absx < 2 && absy < 1 && scale == 0)
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{
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FLOAT d2m1 = (absx - 1) * (absx + 1);
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if (absy >= M_EPSILON)
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d2m1 += absy * absy;
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__real__ result = M_LOG1P (d2m1) / 2;
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}
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else if (absx < 1
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&& absx >= M_LIT (0.5)
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&& absy < M_EPSILON / 2
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&& scale == 0)
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{
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FLOAT d2m1 = (absx - 1) * (absx + 1);
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__real__ result = M_LOG1P (d2m1) / 2;
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}
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else if (absx < 1
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&& absx >= M_LIT (0.5)
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&& scale == 0
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&& absx * absx + absy * absy >= M_LIT (0.5))
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{
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FLOAT d2m1 = M_SUF (__x2y2m1) (absx, absy);
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__real__ result = M_LOG1P (d2m1) / 2;
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}
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else
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{
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FLOAT d = M_HYPOT (absx, absy);
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__real__ result = M_LOG (d) - scale * (FLOAT) M_MLIT (M_LN2);
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}
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__imag__ result = M_ATAN2 (__imag__ x, __real__ x);
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}
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else
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{
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__imag__ result = M_NAN;
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if (rcls == FP_INFINITE || icls == FP_INFINITE)
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/* Real or imaginary part is infinite. */
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__real__ result = M_HUGE_VAL;
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else
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__real__ result = M_NAN;
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}
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return result;
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}
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declare_mgen_alias (__clog, clog)
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