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#include "u.h"
#include "lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#define NA 10 /* max. alarms per clock tick */
#define MAXALARM (3 * NA)
Alarm alarmtab[MAXALARM];
/*
* Insert new into list after where
*/
void
insert(List **head, List *where, List *new)
{
if(where == 0){
new->next = *head;
*head = new;
}else{
new->next = where->next;
where->next = new;
}
}
/*
* Delete old from list. where->next is known to be old.
*/
void
delete(List **head, List *where, List *old)
{
if(where == 0){
*head = old->next;
return;
}
where->next = old->next;
}
Alarm*
newalarm(void)
{
int i;
Alarm *a;
for(i=0,a=alarmtab; i < nelem(alarmtab); i++,a++)
if(a->busy==0 && a->f==0){
a->f = 0;
a->arg = 0;
a->busy = 1;
return a;
}
panic("newalarm");
return 0; /* not reached */
}
Alarm*
alarm(int ms, void (*f)(Alarm*), void *arg)
{
Alarm *a, *w, *pw;
ulong s;
if(ms < 0)
ms = 0;
s = splhi();
a = newalarm();
a->dt = MS2TK(ms);
a->f = f;
a->arg = arg;
pw = 0;
for(w=m->alarm; w; pw=w, w=w->next){
if(w->dt <= a->dt){
a->dt -= w->dt;
continue;
}
w->dt -= a->dt;
break;
}
insert(&m->alarm, pw, a);
splx(s);
return a;
}
void
cancel(Alarm *a)
{
a->f = 0;
}
void
alarminit(void)
{
}
void
checkalarms(void)
{
int i, n, s;
Alarm *a;
void (*f)(Alarm*);
Alarm *alist[NA];
s = splhi();
a = m->alarm;
if(a){
for(n=0; a && a->dt<=0 && n<NA; n++){
alist[n] = a;
delete(&m->alarm, 0, a);
a = m->alarm;
}
if(a)
a->dt--;
for(i = 0; i < n; i++){
f = alist[i]->f; /* avoid race with cancel */
if(f)
(*f)(alist[i]);
alist[i]->busy = 0;
}
}
splx(s);
}
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