provided code

src/userprog/gdt.h

@@ -0,0 +1,15 @@
+#ifndef USERPROG_GDT_H
+#define USERPROG_GDT_H
+
+#include "threads/loader.h"
+
+/* Segment selectors.
+   More selectors are defined by the loader in loader.h. */
+#define SEL_UCSEG       0x1B    /* User code selector. */
+#define SEL_UDSEG       0x23    /* User data selector. */
+#define SEL_TSS         0x28    /* Task-state segment. */
+#define SEL_CNT         6       /* Number of segments. */
+
+void gdt_init (void);
+
+#endif /* userprog/gdt.h */