Add timer
diff --git a/src/timer.c b/src/timer.c
new file mode 100644
index 0000000..72ff1c6
--- /dev/null
+++ b/src/timer.c
@@ -0,0 +1,33 @@
+#include "timer.h"
+#include "pic.h"
+#include "log.h"
+#include "registers.h"
+#include "io.h"
+
+static ulong tick = 0;
+
+static void timer_cb(struct registers regs)
+{
+ kprintf("Timer tick %d\n", tick++);
+}
+
+void init_timer(uint hz)
+{
+ add_interrupt_handler(IRQ_TO_INT(0), timer_cb);
+
+ uint divisor = TIMER_FREQ / hz;
+
+ kprintf("Divisor is %d\n", divisor);
+
+ outb(0x43, 0x36);
+ io_wait();
+ uchar l = divisor & 0xff,
+ h = (divisor >> 8) & 0xff;
+
+ outb(0x40, l);
+ io_wait();
+ outb(0x40, h);
+ io_wait();
+
+ kprintf("Initialized timer\n");
+}