| /* |
| * GRUB -- GRand Unified Bootloader |
| * Copyright (C) 2020 Free Software Foundation, Inc. |
| * |
| * GRUB is free software: you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation, either version 3 of the License, or |
| * (at your option) any later version. |
| * |
| * GRUB is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with GRUB. If not, see <http://www.gnu.org/licenses/>. |
| * |
| * Arithmetic operations that protect against overflow. |
| */ |
| |
| #ifndef GRUB_SAFEMATH_H |
| #define GRUB_SAFEMATH_H 1 |
| |
| #include <grub/compiler.h> |
| |
| /* These appear in gcc 5.1 and clang 3.8. */ |
| #if GNUC_PREREQ(5, 1) || CLANG_PREREQ(3, 8) |
| |
| #define grub_add(a, b, res) __builtin_add_overflow(a, b, res) |
| #define grub_sub(a, b, res) __builtin_sub_overflow(a, b, res) |
| #define grub_mul(a, b, res) __builtin_mul_overflow(a, b, res) |
| |
| #else |
| #error gcc 5.1 or newer or clang 3.8 or newer is required |
| #endif |
| |
| #endif /* GRUB_SAFEMATH_H */ |
