feature: start to implement keyboard handler and better isrs/irqs

headers/interrupts.h

@@ -2,5 +2,19 @@
 
 #include <stdint.h>
 
-void exception_handler(void);
+struct registers {
+	// data segment selector
+	uint32_t ds;
+	// general purpose registers pushed by pusha
+	uint32_t edi, esi, ebp, esp, ebx, edx, ecx, eax;
+	// pushed by isr procedure
+	uint32_t int_no, err_code;
+	// pushed by CPU automatically
+	uint32_t eip, cs, eflags, useresp, ss;
+};
+
+typedef void (*isr_t)(struct registers *);
+
+void isr_handler(struct registers *regs);
 void pic_send_eoi(uint8_t irq);
+void register_interrupt_handler(int index, isr_t handler);