add PIT

src/isr.c

@@ -3,6 +3,7 @@
 #include "../include/types.h"
 #include "../include/screen.h"
 #include "../include/pic.h"
+#include "../include/pit.h"
 
 typedef size_t uword_t;
 struct interrupt_frame
@@ -14,6 +15,7 @@ struct interrupt_frame
     uword_t ss;
 };
 
+__attribute__((interrupt)) void isr_timer(struct interrupt_frame *frame);
 void isr_custom();
 void default_handler();
 
@@ -54,6 +56,7 @@ void isr_install() {
     for(int i = 32; i < 255; i++)
 	idt_set_descriptor(i, (uint32)default_handler, 0x8E);
 
+    idt_set_descriptor(0x20, (uint32)isr_timer, 0x8E);
     idt_set_descriptor(0x21, (uint32)isr_custom, 0x8E);
 
 
@@ -66,6 +69,12 @@ void default_handler()
 
 }
 
+__attribute__((interrupt)) void isr_timer(struct interrupt_frame *frame)
+{
+	pit_init();
+	pic_end_int(0x0);
+}
+
 void handle_keyboard()
 {
 	uint8_t scancode = inb(0x60);
@@ -76,7 +85,7 @@ __attribute__((interrupt)) void isr_custom(struct interrupt_frame *frame)
 {
 	//terminal_writestring("YOOOOO!!!!!! I LOVE KATYA!!!!");
 	handle_keyboard();
-	pic_end_int(0x21);
+	pic_end_int(0x1);
 }
 
 void isr0()