39 lines
1.3 KiB
C
39 lines
1.3 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2020 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*
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* Arithmetic operations that protect against overflow.
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*/
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#ifndef GRUB_SAFEMATH_H
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#define GRUB_SAFEMATH_H 1
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#include <grub/compiler.h>
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/* These appear in gcc 5.1 and clang 8.0. */
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#if GNUC_PREREQ(5, 1) || CLANG_PREREQ(8, 0)
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#define grub_add(a, b, res) __builtin_add_overflow(a, b, res)
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#define grub_sub(a, b, res) __builtin_sub_overflow(a, b, res)
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#define grub_mul(a, b, res) __builtin_mul_overflow(a, b, res)
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#define grub_cast(a, res) grub_add ((a), 0, (res))
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#else
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#error gcc 5.1 or newer or clang 8.0 or newer is required
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#endif
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#endif /* GRUB_SAFEMATH_H */
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