55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
/*
|
|
* VAS_EBOOT -- GRand Unified Bootloader
|
|
* Copyright (C) 2020 Free Software Foundation, Inc.
|
|
*
|
|
* VAS_EBOOT 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.
|
|
*
|
|
* VAS_EBOOT 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 VAS_EBOOT. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
* Arithmetic operations that protect against overflow.
|
|
*/
|
|
|
|
#ifndef VAS_EBOOT_SAFEMATH_H
|
|
#define VAS_EBOOT_SAFEMATH_H 1
|
|
|
|
#include <VasEBoot/compiler.h>
|
|
|
|
/* These appear in gcc 5.1 and clang 8.0. */
|
|
#if GNUC_PREREQ(5, 1) || CLANG_PREREQ(8, 0)
|
|
|
|
#define VasEBoot_add(a, b, res) __builtin_add_overflow(a, b, res)
|
|
#define VasEBoot_sub(a, b, res) __builtin_sub_overflow(a, b, res)
|
|
#define VasEBoot_mul(a, b, res) __builtin_mul_overflow(a, b, res)
|
|
|
|
#define VasEBoot_cast(a, res) VasEBoot_add ((a), 0, (res))
|
|
|
|
/*
|
|
* It's caller's responsibility to check "align" does not equal 0 and
|
|
* is power of 2.
|
|
*/
|
|
#define ALIGN_UP_OVF(v, align, res) \
|
|
({ \
|
|
bool __failed; \
|
|
typeof(v) __a = ((typeof(v))(align) - 1); \
|
|
\
|
|
__failed = VasEBoot_add (v, __a, res); \
|
|
if (__failed == false) \
|
|
*(res) &= ~__a; \
|
|
__failed; \
|
|
})
|
|
|
|
#else
|
|
#error gcc 5.1 or newer or clang 8.0 or newer is required
|
|
#endif
|
|
|
|
#endif /* VAS_EBOOT_SAFEMATH_H */
|