1 files changed, 36 insertions, 0 deletions
diff --git a/src/stem/timer.c b/src/stem/timer.c
new file mode 100644
index 0000000..10651ab
--- /dev/null
+++ b/src/stem/timer.c
@@ -0,0 +1,36 @@
+#include "timer.h"
+#include "idt.h"
+#include "sys.h"
+#include "monitor.h"
+
+static uint32_t tick = 0, frequency = 0, uptime = 0;
+
+void timer_callback(struct registers *regs) {
+	tick++;
+	if (tick == frequency) {
+		uptime++;
+		tick = 0;
+	}
+}
+
+uint32_t timer_uptime() { return uptime; }
+
+uint32_t timer_time() {
+	return (uptime * 1000) + (tick * 1000 / frequency);
+}
+
+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("Timer started\n");
+}