/****************************************************************************** * * Copyright © International Business Machines Corp., 2009 * * 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. * * DESCRIPTION * GCC atomic builtin wrappers * http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html * * AUTHOR * Darren Hart <dvhart@linux.intel.com> * * HISTORY * 2009-Nov-17: Initial version by Darren Hart <dvhart@linux.intel.com> * *****************************************************************************/ #ifndef _ATOMIC_H #define _ATOMIC_H typedef struct { volatile int val; } atomic_t; #define ATOMIC_INITIALIZER { 0 } /** * atomic_cmpxchg() - Atomic compare and exchange * @uaddr: The address of the futex to be modified * @oldval: The expected value of the futex * @newval: The new value to try and assign the futex * * Return the old value of addr->val. */ static inline int atomic_cmpxchg(atomic_t *addr, int oldval, int newval) { return __sync_val_compare_and_swap(&addr->val, oldval, newval); } /** * atomic_inc() - Atomic incrememnt * @addr: Address of the variable to increment * * Return the new value of addr->val. */ static inline int atomic_inc(atomic_t *addr) { return __sync_add_and_fetch(&addr->val, 1); } /** * atomic_dec() - Atomic decrement * @addr: Address of the variable to decrement * * Return the new value of addr-val. */ static inline int atomic_dec(atomic_t *addr) { return __sync_sub_and_fetch(&addr->val, 1); } /** * atomic_set() - Atomic set * @addr: Address of the variable to set * @newval: New value for the atomic_t * * Return the new value of addr->val. */ static inline int atomic_set(atomic_t *addr, int newval) { addr->val = newval; return newval; } #endif