nuclear@86: #include <assert.h>
nuclear@86: #include "mutex.h"
nuclear@86: #include "sched.h"
nuclear@86: #include "intr.h"
nuclear@86: 
nuclear@86: void mutex_lock(mutex_t *m)
nuclear@86: {
nuclear@86: 	int istate = get_intr_state();
nuclear@86: 	disable_intr();
nuclear@86: 
nuclear@86: 	/* sleep while the mutex is held */
nuclear@86: 	while(*m > 0) {
nuclear@86: 		wait(m);
nuclear@86: 	}
nuclear@86: 	/* then grab it... */
nuclear@86: 	(*m)++;
nuclear@86: 
nuclear@86: 	set_intr_state(istate);
nuclear@86: }
nuclear@86: 
nuclear@86: void mutex_unlock(mutex_t *m)
nuclear@86: {
nuclear@86: 	int istate = get_intr_state();
nuclear@86: 	disable_intr();
nuclear@86: 
nuclear@86: 	assert(*m);
nuclear@86: 	/* release the mutex and wakeup everyone waiting on it */
nuclear@86: 	(*m)--;
nuclear@86: 	wakeup(m);
nuclear@86: 
nuclear@86: 	set_intr_state(istate);
nuclear@86: }
nuclear@86: 
nuclear@86: int mutex_trylock(mutex_t *m)
nuclear@86: {
nuclear@86: 	int res = -1, istate = get_intr_state();
nuclear@86: 	disable_intr();
nuclear@86: 
nuclear@86: 	if(*m == 0) {
nuclear@86: 		(*m)++;
nuclear@86: 		res = 0;
nuclear@86: 	}
nuclear@86: 	set_intr_state(istate);
nuclear@86: 	return res;
nuclear@86: }