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81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
/* Copyright (C) 2005-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Richard Henderson <rth@redhat.com>, 2005.
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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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<http://www.gnu.org/licenses/>. */
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#include <stdbool.h>
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#include <math.h>
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#include <complex.h>
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attribute_hidden
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long double _Complex
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__multc3 (long double a, long double b, long double c, long double d)
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{
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long double ac, bd, ad, bc, x, y;
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ac = a * c;
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bd = b * d;
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ad = a * d;
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bc = b * c;
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x = ac - bd;
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y = ad + bc;
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if (isnan (x) && isnan (y))
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{
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/* Recover infinities that computed as NaN + iNaN. */
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bool recalc = 0;
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if (isinf (a) || isinf (b))
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{
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/* z is infinite. "Box" the infinity and change NaNs in
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the other factor to 0. */
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a = __copysignl (isinf (a) ? 1 : 0, a);
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b = __copysignl (isinf (b) ? 1 : 0, b);
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if (isnan (c)) c = __copysignl (0, c);
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if (isnan (d)) d = __copysignl (0, d);
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recalc = 1;
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}
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if (isinf (c) || isinf (d))
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{
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/* w is infinite. "Box" the infinity and change NaNs in
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the other factor to 0. */
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c = __copysignl (isinf (c) ? 1 : 0, c);
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d = __copysignl (isinf (d) ? 1 : 0, d);
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if (isnan (a)) a = __copysignl (0, a);
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if (isnan (b)) b = __copysignl (0, b);
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recalc = 1;
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}
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if (!recalc
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&& (isinf (ac) || isinf (bd)
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|| isinf (ad) || isinf (bc)))
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{
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/* Recover infinities from overflow by changing NaNs to 0. */
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if (isnan (a)) a = __copysignl (0, a);
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if (isnan (b)) b = __copysignl (0, b);
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if (isnan (c)) c = __copysignl (0, c);
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if (isnan (d)) d = __copysignl (0, d);
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recalc = 1;
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}
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if (recalc)
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{
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x = INFINITY * (a * c - b * d);
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y = INFINITY * (a * d + b * c);
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}
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}
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return x + I * y;
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}
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