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#ifndef _SPARC_SEMAPHORE_H
#define _SPARC_SEMAPHORE_H
/* Dinky, good for nothing, just barely irq safe, Sparc semaphores.
*
* I'll write better ones later.
*/
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
atomic_t waiting;
struct wait_queue * wait;
};
#define MUTEX ((struct semaphore) { 1, 0, NULL })
#define MUTEX_LOCKED ((struct semaphore) { 0, 0, NULL })
extern void __down(struct semaphore * sem);
extern void __up(struct semaphore * sem);
/*
* This isn't quite as clever as the x86 side, but the gp register
* makes things a bit more complicated on the alpha..
*/
extern inline void down(struct semaphore * sem)
{
for (;;) {
if (atomic_dec_return(&sem->count) >= 0)
break;
__down(sem);
}
}
extern inline void up(struct semaphore * sem)
{
if (atomic_inc_return(&sem->count) <= 0)
__up(sem);
}
#endif /* !(_SPARC_SEMAPHORE_H) */
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