Move PF_* from exception.c to exception.h, because some students may

wish to pass them around.
Suggested by Godmar Back.

diff --git a/src/userprog/exception.c b/src/userprog/exception.c
index 47bfbc278878595b1cf0fa15d73d374057a994d7..985cd175a1b9b9267b78c4f787219a7843acea2f 100644 (file)
--- a/src/userprog/exception.c
+++ b/src/userprog/exception.c
@@ -114,7 +114,7 @@ kill (struct intr_frame *f)
 
    At entry, the address that faulted is in CR2 (Control Register
    2) and information about the fault, formatted as described in
-   the PF_* macros above, is in F's error_code member.  The
+   the PF_* macros in exception.h, is in F's error_code member.  The
    example code here shows how to parse that information.  You
    can find more information about both of these in the
    description of "Interrupt 14--Page Fault Exception (#PF)" in

diff --git a/src/userprog/exception.h b/src/userprog/exception.h
index f1a1537b99edbfa05b93d21afb3ba2d5f3623dc8..f83e615bb1e010c8723510a99abb01d714c0f275 100644 (file)
--- a/src/userprog/exception.h
+++ b/src/userprog/exception.h
@@ -1,6 +1,11 @@
 #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);