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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
void
lock(Lock *l)
{
int n;
if(up) {
n = up->inlock+2;
up->inlock = n;
if(tas(&l->key) == 0)
return;
for(;;){
while(l->key)
if(conf.nproc == 1) {
up->yield = 1;
sched();
}
up->inlock = n;
if(tas(&l->key) == 0)
return;
}
}
if(tas(&l->key) == 0)
return;
for(;;){
while(l->key)
;
if(tas(&l->key) == 0)
return;
}
}
void
ilock(Lock *l)
{
ulong x;
x = splhi();
if(tas(&l->key) == 0){
l->sr = x;
return;
}
for(;;){
while(l->key)
;
if(tas(&l->key) == 0){
l->sr = x;
return;
}
}
}
int
canlock(Lock *l)
{
if(tas(&l->key))
return 0;
return 1;
}
void
unlock(Lock *l)
{
int n;
l->key = 0;
if(up) {
n = up->inlock-2;
if(n < 0)
n = 0;
up->inlock = n;
}
}
void
iunlock(Lock *l)
{
ulong sr;
sr = l->sr;
l->key = 0;
splx(sr);
}