-#define _PAGE_SILENT_READ (1 << 1) /* synonym */
-#define _PAGE_DIRTY_SHIFT 2
-#define _PAGE_DIRTY (1 << _PAGE_DIRTY_SHIFT) /* The MIPS dirty bit */
-#define _PAGE_SILENT_WRITE (1 << 2)
-#define _CACHE_SHIFT 3
-#define _CACHE_MASK (7 << 3)
+#define _PAGE_DIRTY_SHIFT (_PAGE_VALID_SHIFT + 1)
+#define _PAGE_DIRTY (1 << _PAGE_DIRTY_SHIFT)
+#define _CACHE_SHIFT (_PAGE_DIRTY_SHIFT + 1)
+#define _CACHE_MASK (7 << _CACHE_SHIFT)