int32_t OSSim::eventYield(Pid_t curPid, Pid_t yieldPid)
{
// LOG("OSSim::yield(%d,%d)", curPid, yieldPid);
ProcessId *curProc=ProcessId::getProcessId(curPid);
// The current process should be running
I(curProc->getState()==RunningState);
// get the CPU where the current process is running
CPU_t cpu=curProc->getCPU();
// Get the ProcessId of the new process
ProcessId *yieldProc;
if(yieldPid<0) {
// No specific new process, get next ready process
yieldProc=ProcessId::queueGet(cpu);
} else {
// Specific ready process, get its ProcessId
yieldProc=ProcessId::getProcessId(yieldPid);
// there should be such a process
if(!yieldProc) {
LOG("OSSim::yield(%d) to non existing process???", yieldPid);
return 0;
}
}
// Do nothing if no process to yield to
if(!yieldProc)
return 1;
// Do nothing if the new process already running
if(yieldProc->getState()==RunningState)
return 1;
// The new process should not be suspended
if(yieldProc->getState()==SuspendedState) {
LOG("OSSim::yield(%d) to a suspended process???", yieldPid);
return 0;
}
// The new process should not be pinned to a other processor
if(yieldProc->isPinned()&&(yieldProc->getCPU()!=cpu)) {
LOG("OSSim::yield(%d) to a NOMIGRABLE process in another CPU", yieldPid);
return 0;
}
// Remove current process from the processor
cpus.switchOut(cpu,curProc);
// Put the new process on that processor
cpus.switchIn(cpu,yieldProc);
return 1;
}
