Added a working GDT.

kernel/hal/x86/Makefile

@@ -5,8 +5,8 @@ CPP = g++
 CC = gcc
 LD = ld
 ASFLAGS = -m32
-CFLAGS = -m32 -Wall -g -fno-stack-protector -nostdinc -Ic_include/ -ffreestanding -fbuiltin
+CFLAGS = -m32 -Wall -g -fno-stack-protector -nostdinc -Ic_include/ -ffreestanding -fbuiltin -march=native
-CPPFLAGS = -m32 -Wall -g -fno-stack-protector -nostdinc -std=c++14 -Iinclude/ -Ic_include/ -fno-rtti -fno-exceptions -ffreestanding -fbuiltin
+CPPFLAGS = -m32 -Wall -g -fno-stack-protector -nostdinc -std=c++14 -Iinclude/ -Ic_include/ -fno-rtti -fno-exceptions -ffreestanding -fbuiltin -march=native
 LDFLAGS = -r -melf_i386
 
 hal.o: $(OBJS)

kernel/hal/x86/asm/snippets.S

@@ -0,0 +1,14 @@
+.global loadGDT
+//void _stdcall loadGDT(struct gdtp* ptr);
+loadGDT:
+	mov 0x4(%esp), %eax // Load argument
+	lgdt (%eax)
+	//GDT is loaded now
+	mov $0x10, %ax
+	mov %ax, %ds
+	mov %ax, %es
+	mov %ax, %fs
+	mov %ax, %gs
+	mov %ax, %ss
+	ljmp $0x8, $.1
+.1:

kernel/hal/x86/include/base.hpp

@@ -5,10 +5,12 @@ namespace MTGosHAL {
 	class Output;
 	class Serial;
 	class Screen;
+	class GDT;
 	enum class BG_color: uint16_t;
 	enum class FG_color: uint16_t;
 	extern Serial* debug;
 	extern Screen* out;
 	extern Screen* err;
+	extern GDT* gdt;
 }
 #endif

kernel/hal/x86/include/gdt.hpp

@@ -0,0 +1,31 @@
+#ifndef _GDT_HPP
+#define _GDT_HPP
+#include <stdint.h>
+#define GDT_FLAG_DATASEG 0x02
+#define GDT_FLAG_CODESEG 0x0a
+#define GDT_FLAG_TSS     0x09
+ 
+#define GDT_FLAG_SEGMENT 0x10
+#define GDT_FLAG_RING0   0x00
+#define GDT_FLAG_RING3   0x60
+#define GDT_FLAG_PRESENT 0x80
+ 
+#define GDT_FLAG_4K_GRAN 0x800
+#define GDT_FLAG_32_BIT  0x400
+extern "C" void loadGDT(void * gdtpr);
+namespace MTGosHAL {
+	class GDT {
+		private:
+			uint64_t gdt[7];
+			struct gdtp {
+				uint16_t limit;
+				void* pointer;
+			} __attribute__((packed));
+			struct gdtp fin;
+		public:
+			GDT();
+			auto setEntry(int i, unsigned int base, unsigned int limit, int flags) -> void;
+			auto apply() -> void;
+	};
+}
+#endif

kernel/hal/x86/init/gdt.cpp

@@ -0,0 +1,21 @@
+#include <base.hpp>
+#include <gdt.hpp>
+#include <serial.hpp>
+namespace MTGosHAL {
+	GDT::GDT() {
+		gdt[0]=gdt[1]=gdt[2]=gdt[3]=gdt[4]=gdt[5]=gdt[6]=0x0ull;
+	}
+	auto GDT::setEntry(int i, unsigned int base, unsigned int limit, int flags) -> void {
+		gdt[i] = limit & 0xffffLL;
+		gdt[i] |= (base & 0xffffffLL) << 16;
+		gdt[i] |= (flags & 0xffLL) << 40;
+		gdt[i] |= ((limit >> 16) & 0xfLL) << 48;
+		gdt[i] |= ((flags >> 8 )& 0xffLL) << 52;
+		gdt[i] |= ((base >> 24) & 0xffLL) << 56;
+	}
+	auto GDT::apply() -> void {
+		*debug << "We are now trying to set our GDT. If the CPU triplefaults, something went wrong in MTGosHAL::GDT::apply() or loadGDT().\n";
+		fin={(uint16_t)7*8-1, (void*)gdt};
+		loadGDT((void*)(&fin));
+	};
+}

kernel/hal/x86/init/init.cpp

@@ -2,6 +2,7 @@
 #include <output.hpp>
 #include <serial.hpp>
 #include <textDISP.hpp>
+#include <gdt.hpp>
 namespace MTGosHAL {
 	Serial* debug;
 	Screen* out;
@@ -9,11 +10,20 @@ namespace MTGosHAL {
 	void main() {
 		Serial serialOUT(115200);
 		Screen display;
+		GDT gdt;
 		debug=&serialOUT;
 		err=&display;
 		out=&display;
 		*out << BG_color::BLACK << FG_color::WHITE << "Loading MTGos...\n";
 		*debug << "Hello debugger! This is MTGos version 0.0\nThese logs are probably very long, so please redirect the output to a file.\n";
+		gdt.setEntry(0, 0, 0, 0);
+		gdt.setEntry(1, 0, 0xfffff, GDT_FLAG_SEGMENT | GDT_FLAG_32_BIT | GDT_FLAG_CODESEG | GDT_FLAG_4K_GRAN | GDT_FLAG_PRESENT);
+		gdt.setEntry(2, 0, 0xfffff, GDT_FLAG_SEGMENT | GDT_FLAG_32_BIT | GDT_FLAG_DATASEG | GDT_FLAG_4K_GRAN | GDT_FLAG_PRESENT);
+		gdt.setEntry(3, 0, 0xfffff, GDT_FLAG_SEGMENT | GDT_FLAG_32_BIT | GDT_FLAG_CODESEG | GDT_FLAG_4K_GRAN | GDT_FLAG_PRESENT | GDT_FLAG_RING3);
+		gdt.setEntry(4, 0, 0xfffff, GDT_FLAG_SEGMENT | GDT_FLAG_32_BIT | GDT_FLAG_DATASEG | GDT_FLAG_4K_GRAN | GDT_FLAG_PRESENT | GDT_FLAG_RING3);
+		gdt.setEntry(5, 0, 0xfffff, GDT_FLAG_SEGMENT | GDT_FLAG_32_BIT | GDT_FLAG_TSS     | GDT_FLAG_4K_GRAN | GDT_FLAG_PRESENT);
+		gdt.setEntry(6, 0, 0xfffff, GDT_FLAG_SEGMENT | GDT_FLAG_32_BIT | GDT_FLAG_TSS     | GDT_FLAG_4K_GRAN | GDT_FLAG_PRESENT);
+		gdt.apply();
 		for(;;);
 	}
 }