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/* $OpenBSD: lock.h,v 1.3 2011/03/23 16:54:35 pirofti Exp $ */
/* public domain */
#ifndef _MACHINE_LOCK_H_
#define _MACHINE_LOCK_H_
#include <machine/atomic.h>
typedef volatile u_int __cpu_simple_lock_t __attribute__((__aligned__(16)));
#define __SIMPLELOCK_LOCKED 0
#define __SIMPLELOCK_UNLOCKED 1
static __inline__ void
__cpu_simple_lock_init(__cpu_simple_lock_t *l)
{
*l = __SIMPLELOCK_UNLOCKED;
}
static __inline__ void
__cpu_simple_lock(__cpu_simple_lock_t *l)
{
__cpu_simple_lock_t old;
do {
old = __SIMPLELOCK_LOCKED;
__asm__ __volatile__
("ldcw %1, %0" : "=r" (old), "=m" (l) : "m" (l));
} while (old != __SIMPLELOCK_UNLOCKED);
}
static __inline__ int
__cpu_simple_lock_try(__cpu_simple_lock_t *l)
{
__cpu_simple_lock_t old = __SIMPLELOCK_LOCKED;
__asm__ __volatile__
("ldcw %1, %0" : "=r" (old), "=m" (l) : "m" (l));
return (old == __SIMPLELOCK_UNLOCKED);
}
static __inline__ void
__cpu_simple_unlock(__cpu_simple_lock_t *l)
{
*l = __SIMPLELOCK_UNLOCKED;
}
#endif /* _MACHINE_LOCK_H_ */
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