void sem_pend(sem_struct *sem)
{
cpu_sr_t cpu_sr;
list_node_t *pnode;
thread_struct *pthread;
cpu_sr = save_cpu_sr();
if (sem->value == 0) {
if (!is_empty_list(&sem->wait_list)) {
for (pnode = begin_list(&sem->wait_list);
pnode != end_list(&sem->wait_list);
pnode = next_list(pnode)) {
pthread = entry_list(pnode, thread_struct, node);
if (current_thread->prio < pthread->prio) {
current_thread->state = EVENT_WAIT;
insert_before_list(
pnode,
¤t_thread->node);
break;
}
}
}
if (current_thread->state != EVENT_WAIT) {
current_thread->state = EVENT_WAIT;
insert_back_list(&sem->wait_list, ¤t_thread->node);
}
schedule(SCHED_THREAD_REQUEST);
return;
}
sem->value--;
restore_cpu_sr(cpu_sr);
}
/** Inserts @a d into list @a l. @a d is inserted before the first value in the
* list where d < list->data. @a c is used to compare d to the data in the list.
* O(n) operation.
* @param l The list
* @param d The new data member
* @param c A comparison function.
* @return The new list
*/
struct slist *slist_insert_sorted(struct slist *l, void *d, compare_func c)
{
struct slist *ins = next_list();
struct slist *head = l;
struct slist *prev;
ins->next = NULL;
ins->data = d;
if(head == NULL) return ins;
if(c(d, head->data) < 0) {
ins->next = head;
return ins;
}
prev = head;
l = l->next;
while(l != NULL) {
if(c(d, l->data) < 0) {
ins->next = prev->next;
prev->next = ins;
return head;
}
prev = l;
l = l->next;
}
prev->next = ins;
return head;
}
/** Prepends @a d to list @a l. O(1) operation.
* @param l The list
* @param d The new data member
* @return The new list
*/
struct slist *slist_insert(struct slist *l, void *d)
{
struct slist *head;
head = next_list();
head->next = l;
head->data = d;
return head;
}
/** Appends @a d to the end of list @a l. O(n) operation
* @param l The list
* @param d The new data member
* @return The new list
*/
struct slist *slist_append(struct slist *l, void *d)
{
struct slist *last;
struct slist *head = l;
last = next_list();
last->next = NULL;
last->data = d;
if(head == NULL) return last;
while(l->next != NULL) {
l = l->next;
}
l->next = last;
return head;
}
/**
* @brief time tick advanced
* Maintain time_quantum
*/
void advance_time_tick()
{
cpu_sr_t cpu_sr;
list_node_t *pnode;
thread_struct *pthread;
thread_struct *readyed_thread = NULL;
cpu_sr = save_cpu_sr();
os_time_tick++;
/* If there are delays in the list of threads... */
if (!is_empty_list(&delayed_list)) {
for (pnode = begin_list(&delayed_list);
pnode != end_list(&delayed_list);
pnode = next_list(pnode) ) {
pthread = entry_list(pnode, thread_struct, node);
pthread->delayed_time--;
/* ready to change the status */
if (readyed_thread != NULL) {
delete_list(&readyed_thread->node);
readyed_thread->state = READY;
readyed_thread->time_quantum = TIME_QUANTUM;
insert_back_list(
&ready_list[readyed_thread->prio],
&readyed_thread->node);
prio_exist_flag[readyed_thread->prio] = true;
readyed_thread = NULL;
}
if (pthread->delayed_time <= 0) {
readyed_thread = pthread;
}
}
if (readyed_thread != NULL) {
delete_list(&readyed_thread->node);
readyed_thread->state = READY;
readyed_thread->time_quantum = TIME_QUANTUM;
insert_back_list(
&ready_list[readyed_thread->prio],
&readyed_thread->node);
prio_exist_flag[readyed_thread->prio] = true;
}
}
current_thread->time_quantum--;
restore_cpu_sr(cpu_sr);
}
