provided code

src/userprog/exception.h

@@ -0,0 +1,12 @@
+#ifndef USERPROG_EXCEPTION_H
+#define USERPROG_EXCEPTION_H
+
+/* Page fault error code bits that describe the cause of the exception.  */
+#define PF_P 0x1    /* 0: not-present page. 1: access rights violation. */
+#define PF_W 0x2    /* 0: read, 1: write. */
+#define PF_U 0x4    /* 0: kernel, 1: user process. */
+
+void exception_init (void);
+void exception_print_stats (void);
+
+#endif /* userprog/exception.h */