Finished basic task switching mechansim

PCB is local to a process's address space.
Context switches are written in assembly.
Moved x86 headers to include/x86

include/x86/interrupts.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <stdint.h>
+
+enum interrupt_code_t
+{
+    EXCEPTION_DIV_BY_0 = 0,
+    EXCEPTION_DEBUG = 1,
+    EXCEPTION_NMI = 2,
+    EXCEPTION_BREAKPOINT = 3,
+    EXCEPTION_OVERFLOW = 4,
+    EXCEPTION_OUT_OF_BOUNDS = 5,
+    EXCEPTION_INVALID_OPCODE = 6,
+    EXCEPTION_DEVICE_NOT_AVAILABLE = 7,
+    EXCEPTION_DOUBLE_FAULT = 8,
+    EXCEPTION_INVALID_TSS = 10,
+    EXCEPTION_SEGMENT_NOT_PRESENT = 11,
+    EXCEPTION_STACK_SEGMENT_FAULT = 12,
+    EXCEPTION_GPF = 13,
+    EXCEPTION_PAGE_FAULT = 14,
+    EXCEPTION_x87_FLOATING_POINT = 16,
+    EXCEPTION_ALIGNMENT_CHECK = 17,
+    EXCEPTION_MACHINE_CHECK = 18,
+    EXCEPTION_SIMD_FLOATING_POINT = 19,
+    EXCEPTION_VIRTUALIZATION = 20,
+    EXCEPTION_SECURITY = 30,
+    ISR_APIC_TIMER = 64,
+    ISR_PREEMPT = 65,
+    ISR_AP_START = 127,
+    ISR_SYSCALL = 128
+};
+
+enum isr_type_t
+{
+    INTERRPUT_TASK32 = 5,
+    INTERRPUT_TRAP32 = 15,
+    INTERRPUT_INT32 = 14,
+    INTERRPUT_TRAP16 = 7,
+    INTERRPUT_INT16 = 6
+};
+
+void initialize_gdt();
+
+void initialize_idt();