1 files changed, 34 insertions, 0 deletions
diff --git a/Source/Kernel/MemoryManager/GDT.ns.cpp b/Source/Kernel/MemoryManager/GDT.ns.cpp
new file mode 100644
index 0000000..4fb9803
--- /dev/null
+++ b/Source/Kernel/MemoryManager/GDT.ns.cpp
@@ -0,0 +1,34 @@
+#include "GDT.ns.h"
+
+extern "C" void gdt_flush(u32int);
+
+namespace GDT {
+
+gdt_entry_t gdt_entries[5];
+gdt_ptr_t   gdt_ptr;
+
+void setGate(s32int num, u32int base, u32int limit, u8int access, u8int gran) {
+	gdt_entries[num].base_low = (base & 0xFFFF);
+	gdt_entries[num].base_middle = (base >> 16) & 0xFF;
+	gdt_entries[num].base_high = (base >> 24) & 0xFF;
+
+	gdt_entries[num].limit_low = (limit & 0xFFFF);
+	gdt_entries[num].granularity = (limit >> 16) & 0x0F;
+	gdt_entries[num].granularity |= gran & 0xF0;
+	gdt_entries[num].access = access;
+}
+
+void init() {
+	gdt_ptr.limit = (sizeof(gdt_entry_t) * 5) - 1;
+	gdt_ptr.base = (u32int)&gdt_entries;
+
+	setGate(0, 0, 0, 0, 0);					//Null segment
+	setGate(1, 0, 0xFFFFFFFF, 0x9A, 0xCF);	//Kernel code segment
+	setGate(2, 0, 0xFFFFFFFF, 0x92, 0xCF);	//Kernel data segment
+	setGate(3, 0, 0xFFFFFFFF, 0xFA, 0xCF);	//User code segment
+	setGate(4, 0, 0xFFFFFFFF, 0xF2, 0xCF);	//User data segment
+
+	gdt_flush((u32int)&gdt_ptr);
+}
+
+}