+#define X86_GDT_ENTRY_SIZE 8
+
+#define X86_GDT_ENTRY_NULL 0
+#define X86_GDT_ENTRY_UNUSED 1
+#define X86_GDT_ENTRY_32BIT_CS 2
+#define X86_GDT_ENTRY_32BIT_DS 3
+#define X86_GDT_ENTRY_32BIT_FS 4
+#define X86_GDT_ENTRY_16BIT_CS 5
+#define X86_GDT_ENTRY_16BIT_DS 6
+#define X86_GDT_ENTRY_16BIT_FLAT_CS 7
+#define X86_GDT_ENTRY_16BIT_FLAT_DS 8
+#define X86_GDT_NUM_ENTRIES 9
+
+#define X86_GDT_SIZE (X86_GDT_NUM_ENTRIES * X86_GDT_ENTRY_SIZE)
+
+/* Length of the public header on Intel microcode blobs */
+#define UCODE_HEADER_LEN 0x30