void OSTakeMutex(OSMutex *mutex)
{
OSMakeAtomic();
if(!mutex->val)
{
procEnq(_running, _tasks, &mutex->blocked);
_tasks[_running].status |= _OS_BLOCKED;
OSExitAtomic();
OSSwap();
}
else
mutex->val=0;
OSExitAtomic();
}
// Can only be used by one process.
void OSWait(OSCond *cond, OSMutex *mutex)
{
OSMakeAtomic();
if(!cond->pendingWake)
{
cond->blockedProcess=_running;
_tasks[_running].status |= _OS_BLOCKED;
OSGiveMutex(mutex);
OSMakeAtomic();
// If val is 1 it means no swap took place.
if(mutex->val)
OSSwap();
// Retake the mutex when we resume
OSTakeMutex(mutex);
}
else
cond->pendingWake=0;
OSExitAtomic();
}
void OSTakeSema(TOSSema *sema)
{
unsigned char sreg;
OSMakeAtomic(&sreg);
if(sema->semaval>0)
sema->semaval--;
else
{
// Block current process
_tasks[_running].status |= _OS_BLOCKED;
// Enqueue this task
prioEnq(_running, _tasks, &sema->taskQ);
OSExitAtomic(sreg);
// Call scheduler.
OSSwap();
}
OSExitAtomic(sreg);
}