Fixed tick_delay; it now reschedules a previous synchronous alarm.

This commit is contained in:
Jorrit Herder 2005-05-13 09:33:53 +00:00
parent efa9c84c8b
commit 49b86f3373
2 changed files with 21 additions and 3 deletions

View file

@ -6,7 +6,14 @@
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 */
@ -16,10 +23,20 @@ long ticks; /* number of ticks to wait */
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);
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);
}
if (OK == s) receive(HARDWARE,&m); /* await synchronous alarm */
return(s);
}

View file

@ -52,6 +52,7 @@ image: programs
# rebuild the program or system libraries
programs:
cd ../include && $(MAKE) install
cd ../kernel && $(MAKE)
cd ../servers && $(MAKE) install
cd ../drivers && $(MAKE) install