ref: ad7a3f7f33448e5e1d808c8747916c20da51cd2f
dir: /sys/src/ape/lib/ap/sparc/lock.c/
#define _LOCK_EXTENSION
#include "../plan9/sys9.h"
#include <lock.h>
int	tas(int*);
void
lock(Lock *lk)
{
	while(tas(&lk->val))
		_SLEEP(0);
}
int
canlock(Lock *lk)
{
	if(tas(&lk->val))
		return 0;
	return 1;
}
void
unlock(Lock *lk)
{
	lk->val = 0;
}