apic: init apic timer using pit, not precise on qemu

include/apic.h

@@ -17,4 +17,8 @@ uint32_t ioapic_read(void *ioapicaddr, uint32_t reg);
 void ioapic_write(void *ioapicaddr, uint32_t reg, uint32_t value);
 void ioapic_redirect(int gsi, int vector);
 
-void enable_symmetric_io_mode();
+void enable_symmetric_io_mode();
+
+void init_pit_timer_apic(uint32_t reload_value);
+void init_apic_timer();
+void mask_pit_interrupt();

include/isr.h

@@ -1,6 +1,10 @@
 #ifndef ISR_H
 #define ISR_H
 
+#include <stdint.h>
+
+extern uint32_t timer_ticks;
+
 void isr0();
 void isr1();
 void isr2();