/*
 *  Atomic ops
 *  Copyright (C) 2008 Andreas Öman
 *
 *  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
 *  of the License, 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; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#ifndef HTSATOMIC_H__
#define HTSATOMIC_H__

/**
 * Atomically add 'incr' to *ptr and return the previous value
 */
#if defined(__i386__) || defined(__x86_64__)
static inline int
atomic_add(volatile int *ptr, int incr)
{
  int r;
  asm volatile("lock; xaddl %0, %1" :
	       "=r"(r), "=m"(*ptr) : "0" (incr), "m" (*ptr) : "memory");
  return r;
}
#endif

#endif /* HTSATOMIC_H__ */
