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48 lines
1.7 KiB
C
48 lines
1.7 KiB
C
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/* Narrow floating-point values to their semantic type.
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Copyright (C) 2015-2018 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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<http://www.gnu.org/licenses/>. */
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#ifndef _MATH_NARROW_EVAL_H
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#define _MATH_NARROW_EVAL_H 1
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#include <float.h>
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/* math_narrow_eval reduces its floating-point argument to the range
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and precision of its semantic type. (The original evaluation may
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still occur with excess range and precision, so the result may be
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affected by double rounding.) */
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#if FLT_EVAL_METHOD == 0
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# define math_narrow_eval(x) (x)
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#else
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# if FLT_EVAL_METHOD == 1
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# define excess_precision(type) __builtin_types_compatible_p (type, float)
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# else
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# define excess_precision(type) (__builtin_types_compatible_p (type, float) \
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|| __builtin_types_compatible_p (type, \
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double))
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# endif
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# define math_narrow_eval(x) \
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({ \
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__typeof (x) math_narrow_eval_tmp = (x); \
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if (excess_precision (__typeof (math_narrow_eval_tmp))) \
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__asm__ ("" : "+m" (math_narrow_eval_tmp)); \
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math_narrow_eval_tmp; \
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})
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#endif
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#endif /* math-narrow-eval.h */
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