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#include "timer.h"
#include "task.h"
#include "idt.h"
#include <mem/mem.h>
#include <core/sys.h>
#include <core/monitor.h>
static uint32_t tick = 0, frequency = 0, uptime = 0;
static void timer_callback(registers *regs);
static void timer_wakeUpSleepingThreads();
/* Called by kmain. Sets up the PIT and the IRQ0 handler. */
void timer_init(uint32_t freq) {
frequency = freq;
idt_handleIrq(0, timer_callback);
uint32_t divisor = 1193180 / freq;
outb(0x43, 0x36); //Command byte
uint8_t l = (divisor & 0xFF), h = (divisor >> 8);
outb(0x40, l);
outb(0x40, h);
monitor_write("[PIT] ");
}
/* Accessor function to get machine uptime. */
uint32_t timer_uptime() { return uptime; }
/* Accessor function, gets uptime in miliseconds. */
uint32_t timer_time() {
return (uptime * 1000) + (tick * 1000 / frequency);
}
/* Called when IRQ0 fires. Updates the uptime variable.
DOES NOT provoke a task switch. The task switch is called in idt.c (IRQ handler). */
void timer_callback(registers *regs) {
tick++;
if (tick == frequency) {
uptime++;
tick = 0;
}
timer_wakeUpSleepingThreads();
}
//************************************************ SLEEP FUNCTIONS *****************
static struct sleeping_thread {
uint32_t wakeup_time;
struct thread *thread;
sleeping_thread *next;
} *sleeping_threads = 0;
/* Makes the current thread sleep. */
void thread_sleep(uint32_t msecs) {
if (current_thread == 0) return;
// Create the sleeping_thread structure
sleeping_thread *sf = (sleeping_thread*)kmalloc(sizeof(sleeping_thread)), *tmp;
sf->wakeup_time = timer_time() + msecs;
sf->thread = current_thread;
//Insert it at the right place
if (sleeping_threads == 0 || sleeping_threads->wakeup_time >= sf->wakeup_time) {
sf->next = sleeping_threads;
sleeping_threads = sf;
} else {
tmp = sleeping_threads;
while (1) {
if (tmp->next == 0 || tmp->next->wakeup_time >= sf->wakeup_time) {
sf->next = tmp->next;
tmp->next = sf;
break;
}
tmp = tmp->next;
}
}
thread_goInactive();
}
void timer_wakeUpSleepingThreads() {
uint32_t time = timer_time();
while (sleeping_threads != 0 && sleeping_threads->wakeup_time <= time) {
sleeping_thread *tmp = sleeping_threads;
tmp->thread->wakeUp();
sleeping_threads = tmp->next;
kfree(tmp);
}
}
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