PUBLIC int tick_delay(ticks)
long ticks; /* number of ticks to wait */
{
- message m;
+/* This function uses the synchronous alarm to delay for a while. This works
+ * even if a previous synchronous alarm was scheduled, because the remaining
+ * tick of the previous alarm are returned so that it can be rescheduled.
+ * Note however that a long tick_delay (longer than the remaining time of the
+ * previous) alarm will also delay the previous alarm.
+ */
+ message m, m_alarm;
+ clock_t time_left;
int s;
if (ticks <= 0) return; /* check for robustness */
m.ALRM_EXP_TIME = ticks; /* request message after ticks */
m.ALRM_ABS_TIME = 0; /* ticks are relative to now */
s = _taskcall(SYSTASK, SYS_SYNCALRM, &m);
+ if (s != OK) return(s);
- if (OK == s) receive(HARDWARE,&m); /* await synchronous alarm */
- return(s);
+ receive(HARDWARE,&m_alarm); /* await synchronous alarm */
+
+ /* Check if we must reschedule the current alarm. */
+ if (m.ALRM_TIME_LEFT > 0) {
+ printf("tick_delay: reschedule alarm\n");
+ m.ALRM_EXP_TIME = m.ALRM_TIME_LEFT - ticks;
+ if (m.ALRM_EXP_TIME <= 0)
+ m.ALRM_EXP_TIME = 1;
+ s = _taskcall(SYSTASK, SYS_SYNCALRM, &m);
+ }
+ return(s);
}
# rebuild the program or system libraries
programs:
+ cd ../include && $(MAKE) install
cd ../kernel && $(MAKE)
cd ../servers && $(MAKE) install
cd ../drivers && $(MAKE) install