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45 lines
1.6 KiB
C
45 lines
1.6 KiB
C
/* Compute x * y + z as ternary operation.
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Copyright (C) 2011-2012 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by David Flaherty <flaherty@linux.vnet.ibm.com>.
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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 <math.h>
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#include <math_ldbl_opt.h>
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long double
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__fmal (long double x, long double y, long double z)
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{
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/* An IBM long double 128 is really just 2 IEEE64 doubles, and in
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* the case of inf/nan only the first double counts. So we use the
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* (double) cast to avoid any data movement. */
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if ((finite ((double)x) && finite ((double)y)) && isinf ((double)z))
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return (z);
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/* If z is zero and x are y are nonzero, compute the result
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as x * y to avoid the wrong sign of a zero result if x * y
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underflows to 0. */
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if (z == 0 && x != 0 && y != 0)
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return x * y;
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return (x * y) + z;
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}
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#ifdef IS_IN_libm
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long_double_symbol (libm, __fmal, fmal);
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#else
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long_double_symbol (libc, __fmal, fmal);
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#endif
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