wip: better way of handling thread switch (iret in the switch)

headers/scheduler.h

@@ -1,3 +1,5 @@
 #pragma once
 
-void scheduler(void);
+#include <stdint.h>
+
+void scheduler(uint32_t *esp);

headers/thread.h

@@ -24,4 +24,4 @@ struct tcb {
 
 struct tcb *create_thread(struct pcb *process, void (*entry)(void));
 void delete_thread(struct tcb *thread);
-void switch_thread(struct tcb *thread_to_switch);
+void switch_thread(uint32_t *esp);