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/*
* Copyright 2024 Great Scott Gadgets <info@greatscottgadgets.com>
*
* This file is part of HackRF.
*
* This program 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 2, or (at your option)
* any later version.
*
* This program 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 this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef __LOCKING_H__
#define __LOCKING_H__
#include <stdint.h>
#include <libopencm3/cm3/sync.h>
/* Primitives for implementing locking.
*
* Must always be used in a pair, with a call to load_exclusive being
* followed immediately or near-immediately by a call to store_exclusive().
* Failure to observe this rule may lead to undefined results. */
// Use ldrex and strex directly if available.
// Otherwise, disable interrupts to ensure exclusivity.
#if defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__)
#define load_exclusive __ldrex
#define store_exclusive __strex
#else
static inline uint32_t load_exclusive(volatile uint32_t* addr)
{
__asm volatile("cpsid i" ::: "memory");
return *addr;
}
static inline uint32_t store_exclusive(uint32_t val, volatile uint32_t* addr)
{
*addr = val;
__asm volatile("cpsie i" ::: "memory");
return 0;
}
#endif
#endif /* __LOCKING_H__ */
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