Kernel: move GDT initialization to boot.S

kernel/include/kernel/GDT.h

@@ -1,8 +1,44 @@
 #pragma once
 
+#include <stdint.h>
+
 namespace GDT
 {
 
-	void initialize();
+	union SegmentDesriptor
+	{
+		struct
+		{
+			uint16_t	limit_lo;
+			uint16_t	base_lo;
+			uint8_t		base_hi1;
+
+			uint8_t		type			: 4;
+			uint8_t		system			: 1;
+			uint8_t		DPL				: 2;
+			uint8_t		present			: 1;
+
+			uint8_t		limit_hi		: 4;
+			uint8_t		flags			: 4;
+
+			uint8_t		base_hi2;
+		} __attribute__((packed));
+		
+		struct
+		{
+			uint32_t low;
+			uint32_t high;
+		} __attribute__((packed));
+
+	} __attribute__((packed));
+
+	struct GDTR
+	{
+		uint16_t size;
+		void* address;
+	} __attribute__((packed));
+
+	extern "C" GDTR g_gdtr[];
+	extern "C" SegmentDesriptor g_gdt[];
 
 }