ptr_t slot_remove(ptr_t p, ptr_t c)
{
bool isFirst = p == MAX_TIMERS;
bool isLast = c == slot[c].next;
bool isOnly = isFirst && isLast;
if (isOnly) {
first = MAX_TIMERS;
} else if (isFirst) {
first = slot[c].next;
} else if (isLast) {
slot[p].next = p;
} else {
slot[p].next = slot[c].next;
}
if (isOnly) {
timer_unset();
} else if (isFirst) {
timer_set(slot[first].cmp);
}
slot[c].next = MAX_TIMERS;
return isFirst ? first : slot[p].next;
}
interrupt(TIMERA0_VECTOR) __attribute__((naked)) timer_isr_ccr0(void)
{
__enter_isr();
if (overflow_interrupt[0] == timer_round) {
timer_unset(0);
int_handler(0);
}
__exit_isr();
}
interrupt(TIMERA1_VECTOR) __attribute__((naked)) timer_isr(void)
{
__enter_isr();
short taiv_reg = TAIV;
if (taiv_reg == 0x0A) {
/* TAIV = 0x0A means overflow */
DEBUG("Overflow\n");
timer_round++;
}
else {
short timer = taiv_reg >> 1;
/* check which CCR has been hit and if the overflow counter
for this timer has been reached (or exceeded);
there is indeed a race condition where an hwtimer
due to fire in the next round can be set after
the timer's counter has overflowed but *before*
timer_round incrementation has occured (when
interrupts are disabled for any reason), thus
effectively setting the timer one round in the past! */
int16_t round_delta = overflow_interrupt[timer] - timer_round;
/* in order to correctly handle timer_round overflow,
we must fire the timer when, for example,
timer_round == 0 and overflow_interrupt[timer] == 65535;
to that end, we compute the difference between the two
on a 16-bit signed integer: any difference >= +32768 will
thus overload to a negative number; we should then
correctly fire "overdue" timers whenever the case */
if (round_delta <= 0) {
timer_unset(timer);
int_handler(timer);
}
}
__exit_isr();
}
void timer_int()
{
slot_t c = slot[first];
slot[first].next = MAX_TIMERS;
#ifndef NDEBUG
timer_t now = timer_now();
if (in_range(timer_tracked_get(), c.cmp, now)) {
DBG static timer_t timer_late_max;
timer_late_max = MAX(timer_late_max, now - c.cmp);
}
#endif
if (c.next == first) {
first = MAX_TIMERS;
timer_unset();
} else {
timer_tracked = c.cmp;
first = c.next;
timer_set(slot[first].cmp);
}
sch_add(c.func);
}
void hwtimer_arch_unset(short timer)
{
timer_unset(timer);
}
