void timer_isr(void) {
CPU_TIMER_START_OF_ISR();
CPU_DEBUG_TICK_START();
BYTE count=0;
KERNEL_TIMER_T * timer_p;
PRESTO_PRIORITY_T current_pri;
// update the system clock
clock_add_ms(&system_clock,PRESTO_KERNEL_MSPERTICK);
// schedule a hardware timer interrupt one tick into the future
CPU_TIMER_RESTART();
// find out the priority of the current running task
current_pri=presto_priority_get(kernel_current_task());
while ((timer_list!=NULL)&&(clock_compare(&timer_list->delivery_time,&system_clock)<=0)) {
// save a pointer to the first timer in the list
timer_p=timer_list;
// remove timer from master list
timer_list=timer_list->next; // we know that timer_list!=NULL
kernel_trigger_set_noswitch(timer_p->owner_tid, timer_p->trigger);
if (timer_p->timer_period>0) {
// This timer is a repeating timer.
// Keep the structure, but update the delivery time.
clock_add_ms(&timer_p->delivery_time,timer_p->timer_period);
timer_insert_into_master_list(timer_p);
}
// indicate that a timer expired, and that it made a high priority task ready
if (presto_priority_get(timer_p->owner_tid)>current_pri) count++;
}
CPU_DEBUG_TICK_END();
if (count>0) {
kernel_context_switch();
}
CPU_TIMER_END_OF_ISR();
}
void timers_updateNearest(){
uint8_t min=0;
Clock* minc=NULL;
for(uint8_t i=timers_stopwatch_count();i<timers_count();i++){
Timer* t=timers_get(i);
Clock* c=timer_getNextFinish(t);
if(c==NULL){
continue;
}
if(minc==NULL||clock_compare(minc,c)>0){
clock_destroy(minc);
minc=c;
min=i;
}else{
clock_destroy(c);
}
}
nearest=min;
scheduler_update(minc);
}
static void timer_insert_into_master_list(KERNEL_TIMER_T * timer_p) {
CPU_LOCK_T lock;
KERNEL_TIMER_T ** p0;
KERNEL_TIMER_T * p1;
cpu_lock_save(lock);
// Start at the head, look at delivery times.
p0=&timer_list;
p1=timer_list;
while (1) {
if ((p1==NULL)||(clock_compare(&p1->delivery_time,&timer_p->delivery_time)>0)) {
// Insert our item between p0 and p1
timer_p->next=p1;
*p0=timer_p;
break; // out of the while (1) loop
}
p0=&(p1->next);
p1=p1->next;
}
cpu_unlock_restore(lock);
}