1 files changed, 38 insertions, 0 deletions
diff --git a/kernel/arch/x86_64/gdt.h b/kernel/arch/x86_64/gdt.h
new file mode 100644
index 0000000..4f68977
--- /dev/null
+++ b/kernel/arch/x86_64/gdt.h
@@ -0,0 +1,38 @@
+#ifndef GDT_H
+#define GDT_H
+
+#include <stdint.h>
+
+struct GDTR {
+    uint16_t size;
+    uint64_t offset;
+}__attribute__((packed));
+
+struct SegDesc {
+    uint16_t limit_low;
+    uint16_t base_low;
+    uint8_t base_mid;
+    uint8_t access;
+    uint8_t flag_limit_high;
+    uint8_t base_high;
+}__attribute__((packed));
+
+// tss segment descriptor is larger than the normal ones
+struct TssSegDesc {
+    uint16_t limit_low;
+    uint16_t base1; // lowest base
+    uint8_t base2;
+    uint8_t access;
+    uint8_t flag_limit_high; // both in the same 8 bits
+    uint8_t base3;
+    uint32_t base4; // highest base
+    uint32_t reserved;
+}__attribute__((packed));
+
+void gdt_entry(SegDesc* seg, uint32_t base, uint32_t limit, uint8_t access, uint8_t flags);
+void gdt_tss_entry(TssSegDesc* seg, uint64_t base, uint32_t limit, uint8_t access, uint8_t flags);
+
+extern "C" void load_gdt(GDTR*);
+extern "C" void reload_segments();
+
+#endif
+\ No newline at end of file