www.pudn.com > LFYOS.zip > v.c

#include"kernel.h" 
 
#define WRONG_THREAD_ID		-1 
#define WRONG_SEMAPHORE_ID	-2 
#define WRONG_THREAD_STATE	-3 
#define WRONG_CAPABILITY	-4 
 
static int v(int semaphore_id,int *steps,struct capability *cap) 
{ 
	struct semaphore *s; 
	struct thread *t; 
	struct return_stack *rt; 
	int i,thread_id,fr_th,ba_th,my_step; 
 
	if((semaphore_id<0)||(semaphore_id>=SEMAPHORE_NUMBER)) 
		return WRONG_SEMAPHORE_ID; 
	s=&(os->semaphore[semaphore_id]); 
	if(s->process<0) 
		return WRONG_SEMAPHORE_ID; 
	if(!KERNEL_COMPARE_CAPABILITY(s->capability,(*cap))) 
		return WRONG_CAPABILITY; 
	if((my_step=(*steps))==0){ 
		*steps=s->value; 
		return 0; 
	}; 
	for(i=0;;i++){ 
		thread_id=s->thread_ring; 
		if(my_step>0){ 
			if((thread_id<0)||(i>=my_step)){ 
				s->value=s->value+my_step-i; 
				break; 
			} 
		}else{ 
			if(thread_id<0) 
				break; 
		}; 
		s->value++; 
		t=&(os->thread[thread_id]); 
		fr_th=t->sem_front;ba_th=t->sem_back; 
		if(fr_th==thread_id) 
			s->thread_ring=-1; 
		else{ 
			s->thread_ring=fr_th; 
			os->thread[fr_th].sem_back=ba_th; 
			os->thread[ba_th].sem_front=fr_th; 
		} 
		t->sleep_semaphore=(-1); 
		if(t->set_v_operation_result_flag){ 
			rt=&(t->return_stack[t->return_stack_top-1]); 
			if(t->return_stack_topreturn_stack_top>0) 
				rt->environment.system_call=i+2; 
		} 
		insert_into_heap(thread_id); 
	} 
	*steps=s->value; 
	return i; 
} 
int v_thread(int thread_id) 
{ 
	int value; 
	struct thread *t; 
	struct semaphore *s; 
 
	if((thread_id<0)||(thread_id>=THREAD_NUMBER)) 
		return(WRONG_THREAD_ID); 
	t=&(os->thread[thread_id]);	 
	if(t->state!=SLEEP) 
		return(WRONG_THREAD_STATE); 
	s=&(os->semaphore[t->sleep_semaphore]); 
	if(s->process<0) 
		return WRONG_SEMAPHORE_ID; 
	s->thread_ring=thread_id; 
	value=1; 
	return(v(t->sleep_semaphore,&value,&(os->system_capability))); 
} 
 
int system_call_v(int semaphore_id,int *steps,struct capability *cap) 
{ 
	if(semaphore_id==0) 
		return WRONG_SEMAPHORE_ID; 
	else 
		return v(semaphore_id,steps,cap); 
}