+/** The mode_X tarval 'unreachable'. */
+extern tarval *tarval_unreachable;
+/** Returns the mode_X tarval 'unreachable'. */
+tarval *get_tarval_unreachable(void);
+
+/** The mode_X tarval 'reachable'. */
+extern tarval *tarval_reachable;
+/** Returns the mode_X tarval 'reachable'. */
+tarval *get_tarval_reachable(void);
+
+/** The 'top' tarval. This is just another name for the 'undefined' tarval. */
+#define tarval_top tarval_undefined
+/** Returns the 'top' tarval. */
+#define get_tarval_top() get_tarval_undefined()
+
+/** The 'bottom' tarval. This is just another name for the 'bad' tarval. */
+#define tarval_bottom tarval_bad
+/** Returns the 'bottom' tarval. */
+#define get_tarval_bottom() get_tarval_bad()
+