| 1 | /* Narrow floating-point values to their semantic type. |
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| 2 | Copyright (C) 2015-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #ifndef _MATH_NARROW_EVAL_H |
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| 20 | #define _MATH_NARROW_EVAL_H 1 |
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| 21 | |
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| 22 | #include <float.h> |
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| 23 | |
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| 24 | /* math_narrow_eval reduces its floating-point argument to the range |
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| 25 | and precision of its semantic type. (The original evaluation may |
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| 26 | still occur with excess range and precision, so the result may be |
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| 27 | affected by double rounding.) */ |
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| 28 | #if FLT_EVAL_METHOD == 0 |
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| 29 | # define math_narrow_eval(x) (x) |
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| 30 | #else |
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| 31 | # if FLT_EVAL_METHOD == 1 |
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| 32 | # define excess_precision(type) __builtin_types_compatible_p (type, float) |
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| 33 | # else |
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| 34 | # define excess_precision(type) (__builtin_types_compatible_p (type, float) \ |
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| 35 | || __builtin_types_compatible_p (type, \ |
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| 36 | double)) |
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| 37 | # endif |
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| 38 | # define math_narrow_eval(x) \ |
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| 39 | ({ \ |
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| 40 | __typeof (x) math_narrow_eval_tmp = (x); \ |
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| 41 | if (excess_precision (__typeof (math_narrow_eval_tmp))) \ |
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| 42 | __asm__ ("" : "+m" (math_narrow_eval_tmp)); \ |
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| 43 | math_narrow_eval_tmp; \ |
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| 44 | }) |
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| 45 | #endif |
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| 46 | |
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| 47 | #endif /* math-narrow-eval.h */ |
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| 48 | |
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