void init_timer() {
t_counter = 0;
active_timer_count = 0;
int i;
//Clear the event timer table
for(i = 0; i < 10; i++)
event_timer[i].p = (process*)0;
init_pic();
init_time_chip(1000); //We use this initial low speed for MIPS calc //UPDATE: As of now, we're just doing it because we want a steady ~1ms timebase for timer functions
installInterrupt(TIMER_INT_NUM, &_handle_timerInt, 3);
installInterrupt(0xE7, &_spurious_handler, 3);
}
void do_mips_calc(void (*cb)(unsigned int)) {
installInterrupt(TIMER_INT_NUM, &_calc_mips, 3);
reentry_call = cb;
state = 1;
__asm__ ("jmp _mips_loop\n");
}
//Stop the timer, update the frequency, and turn it back on
void throttle_timer(unsigned int freq) {
timer_off();
init_time_chip(freq); //Full throttle is 596591
timer_on();
installInterrupt(TIMER_INT_NUM, &_handle_timerInt, 3); //Make sure the normal handler is installed
}
void c_calc_mips() {
static unsigned int state = 1;
//Acknowledge the timer interrupt
timer_int_ack();
if(state) {
//We're starting up, so update the state and
//re-enter the MIPS loop
state = 0;
__asm__ ("jmp _mips_loop\n");
} else {
//Do MIPS calculation from counter and return to
//kernel startup process
_mips_counter = _mips_counter * 400; //4 instructions in the loop and 100Hz sample window
resetProcessCounter();
installInterrupt(TIMER_INT_NUM, &_handle_timerInt, 3); //Reset the vector to the normal timer handler
(*reentry_call)(_mips_counter);
}
}
//Open an IRQ channel on the PIC and set up the IRQ handler to pass a message to
//the registered process
//NOTE: irq_number is offset by one (eg: irq_number 0 implies irq 1) because
//irq 0 itself is reserved for the system timer regardless.
unsigned int irq_register(unsigned int irq_number, process *requesting_proc) {
//Return failure if a nonsense IRQ was requested
if(irq_number > 15)
return 0;
//map the process
DEBUG("\nRegistered IRQ slot #");
DEBUG_HD(irq_number);
DEBUG("/interrupt 0x");
DEBUG_HD(irq_number + 0xE0);
DEBUG_PCHAR('\n');
irq_process[irq_number - 1] = requesting_proc;
//map the handler into the right interrupt vector, assuming it's not
//already set up (E0 is irq 0)
installInterrupt(irq_number + 0xE0, irq_handler[irq_number - 1], 3);
//Open up the associated PIC channel
enable_irq(irq_number);
//For now, we can't really fail so we just return OK
return 1;
}
