-void proc_permit(void)
-{
- /* No need to protect against interrupts here. */
- --CurrentProcess->forbid_cnt;
-}
-
-static void (*irq_handlers[100])(void); // FIXME
-
-
-void proc_preempt(void)
-{
- TRACE;
-
- ATOMIC(LIST_ASSERT_VALID(&ProcReadyList));
-
- IRQ_DISABLE;
- /* Poll on the ready queue for the first ready process */
- while (!(CurrentProcess = (struct Process *)list_remHead(&ProcReadyList)))
- {
- /*
- * Make sure we physically reenable interrupts here, no matter what
- * the current task status is. This is important because if we
- * are idle-spinning, we must allow interrupts, otherwise no
- * process will ever wake up.
- *
- * During idle-spinning, an interrupt can occur and it may
- * modify \p ProcReadyList. To ensure that compiler reload this
- * variable every while cycle we call CPU_MEMORY_BARRIER.
- * The memory barrier ensure that all variables used in this context
- * are reloaded.
- */
- IRQ_ENABLE;
- CPU_IDLE;
- MEMORY_BARRIER;
- IRQ_DISABLE;
- }
- IRQ_ENABLE;
-}
-
-void proc_preempt_timer(void)
-{
- // TODO: check Quantum
-
- alarm(1);
- ATOMIC(SCHED_ENQUEUE(CurrentProcess));
- proc_schedule();
-}
-
-void proc_schedule(void)
-{
- kill(0, SIGUSR1);
-}
-
-void proc_yield(void)
-{
- ATOMIC(SCHED_ENQUEUE(CurrentProcess));
-
- proc_schedule();
-}
-
-/* signal handler */
-void irq_entry(int signum)
-{
- Process *old_process;
-
- TRACEMSG("storing %p:%s", CurrentProcess, CurrentProcess->monitor.name);
- CurrentProcess->leaving = false;
- getcontext(&CurrentProcess->context);
- /* We get here in two ways: directly, and after setcontext() below */
-
- if (CurrentProcess->leaving)
- {
- TRACEMSG("leaving to %p:%s", CurrentProcess, CurrentProcess->monitor.name);
- return;
- }
-
- old_process = CurrentProcess;
-
- irq_handlers[signum]();
-
- if (old_process != CurrentProcess)
- {
- TRACEMSG("launching %p:%s", CurrentProcess, CurrentProcess->monitor.name);
- CurrentProcess->leaving = true;
- setcontext(&CurrentProcess->context);
- /* not reached */
- }
-
- TRACEMSG("keeping %p:%s", CurrentProcess, CurrentProcess->monitor.name);
-}
-
-void preempt_init(void)
-{
- struct sigaction act;
- act.sa_handler = irq_entry;
- sigemptyset(&act.sa_mask);
- sigaddset(&act.sa_mask, SIGUSR1);
- sigaddset(&act.sa_mask, SIGALRM);
- act.sa_flags = SA_RESTART; /* | SA_SIGINFO; */
-
- irq_handlers[SIGUSR1] = proc_preempt;
- irq_handlers[SIGALRM] = proc_preempt_timer;
- sigaction(SIGUSR1, &act, NULL);
- sigaction(SIGALRM, &act, NULL);
-
- alarm(1);
-}