void Kernel(tf_t *tf_p) // kernel begins its control upon/after interrupt
{
int pid;
pcbs[ cur_pid ].tf_p = tf_p; // save for cur_pid which may change
switch( tf_p->intr_id )
{
case TIMER_INTR:
TimerISR();
break;
case IRQ7_INTR:
IRQ7ISR(); // service parallel printer port event
break;
case GETPID_INTR:
tf_p->eax = cur_pid;
break;
case SLEEP_INTR:
SleepISR();
break;
case SPAWN_INTR:
pid = DeQ( &avail_q ); // get pid and put in ebx can be in Kernel()
pcbs[ cur_pid ].tf_p->ebx = pid; // child PID, could be -1
if( pid == -1 ) break; // no more process
SpawnISR(pid, (func_ptr_t) pcbs[ cur_pid ].tf_p->eax);
break;
case SEMINIT_INTR:
SemInitISR();
break;
case SEMWAIT_INTR:
SemWaitISR(tf_p->eax);
break;
case SEMPOST_INTR:
SemPostISR(tf_p->eax);
break;
case MSGSND_INTR:
MsgSndISR();
break;
case MSGRCV_INTR:
MsgRcvISR();
break;
case IRQ3_INTR:
case IRQ4_INTR:
IRQ34ISR();
break;
case FORK_INTR:
pid = DeQ( &avail_q );
ForkISR(pid);
pcbs[ cur_pid ].tf_p->ebx = pid;
break;
case WAIT_INTR: //cons_printf("Wait Intr\n");
WaitISR();
break;
case EXIT_INTR: //cons_printf("Exit Intr\n");
ExitISR();
break;
}
Scheduler(); // find same/new process to run
Loader(pcbs[ cur_pid ].tf_p); // load it to run
} // Kernel()
void Kernel(tf_t *tf_p) // kernel directly enters here when interrupt occurs
{
// Save "tf_p" to pcbs[cur_pid].tf_p for future resume of process runtime
pcbs[cur_pid].tf_p = tf_p;
// tf_p->intr_id tells what intr made CPU get here, pushed in entry.S
switch(tf_p->intr_id)
{
case TIMER_INTR:
TimerISR(); // this must include dismissal of timer interrupt
break;
case IRQ7_INTR:
IRQ7ISR();
break;
case SLEEP_INTR:
SleepISR(tf_p->eax);
break;
case GETPID_INTR:
tf_p->eax = cur_pid;
break;
case SPAWN_INTR:
if (EmptyQ(&avail_q)) {
cons_printf("No more available PIDs!\n");
tf_p->ebx = -1;
}
else {
tf_p->ebx = DeQ(&avail_q);
SpawnISR((int) tf_p->ebx, (func_ptr_t) tf_p->eax);
}
break;
case SEMINIT_INTR:
tf_p->ebx = SemInitISR(tf_p->eax);
break;
case SEMWAIT_INTR:
SemWaitISR(tf_p->eax);
break;
case SEMPOST_INTR:
SemPostISR(tf_p->eax);
break;
case MSGSND_INTR:
MsgSndISR();
break;
case MSGRCV_INTR:
MsgRcvISR();
break;
}
Scheduler(); // select a process to run
Loader(pcbs[cur_pid].tf_p); // run the process selected
}
