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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
static Alarms alarms;
static Rendez alarmr;
void
alarmkproc(void*)
{
Proc *rp;
ulong now, when;
while(waserror())
;
for(;;){
now = MACHP(0)->ticks;
qlock(&alarms);
for(rp = alarms.head; rp != nil; rp = rp->palarm){
if((when = rp->alarm) == 0)
continue;
if((long)(now - when) < 0)
break;
if(!canqlock(&rp->debug))
break;
if(rp->alarm != 0){
postnote(rp, 0, "alarm", NUser);
rp->alarm = 0;
}
qunlock(&rp->debug);
}
alarms.head = rp;
qunlock(&alarms);
sleep(&alarmr, return0, 0);
}
}
/*
* called every clock tick on cpu0
*/
void
checkalarms(void)
{
Proc *p;
ulong now, when;
p = alarms.head;
if(p != nil){
now = MACHP(0)->ticks;
when = p->alarm;
if(when == 0 || (long)(now - when) >= 0)
wakeup(&alarmr);
}
}
ulong
procalarm(ulong time)
{
Proc **l, *f;
ulong when, old;
old = up->alarm;
if(old)
old = tk2ms(old - MACHP(0)->ticks);
if(time == 0) {
up->alarm = 0;
return old;
}
when = ms2tk(time)+MACHP(0)->ticks;
if(when == 0)
when = 1;
qlock(&alarms);
l = &alarms.head;
for(f = *l; f; f = f->palarm) {
if(up == f){
*l = f->palarm;
break;
}
l = &f->palarm;
}
up->palarm = 0;
if(alarms.head) {
l = &alarms.head;
for(f = *l; f; f = f->palarm) {
time = f->alarm;
if(time != 0 && (long)(time - when) >= 0) {
up->palarm = f;
*l = up;
goto done;
}
l = &f->palarm;
}
*l = up;
}
else
alarms.head = up;
done:
up->alarm = when;
qunlock(&alarms);
return old;
}
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