x86_atomic.c
1.36 KB
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/*
* Copyright (C) 2014-2015 René Kijewski <rene.kijewski@fu-berlin.de>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @ingroup x86-multithreading
* @{
*
* @file
* @brief Atomic arithmetic for the x86 port.
*
* @author René Kijewski <rene.kijewski@fu-berlin.de>
*
* @}
*/
#include <stdint.h>
#include "atomic.h"
int atomic_cas(atomic_int_t *dest, int known_value, int new_value)
{
uint8_t successful;
__asm__ volatile ("lock cmpxchgl %2, %0\n"
"seteb %1"
: "+m"(ATOMIC_VALUE(*dest)), "=g"(successful)
: "r"(new_value), "a"(known_value)
: "flags");
return successful;
}