Intial commit.

Chris's intial work on the extenstions.

tools/gdb/python/chains.py

@@ -0,0 +1,43 @@
+#
+# RTEMS Chains Support
+# Copyright 2010 Chris Johns (chrisj@rtems.org)
+#
+# $Id$
+#
+
+import gdb
+
+class node:
+    """Manage the Chain_Node."""
+
+    def __init__(self, node_val):
+        self.node_val = node_val
+
+    def null(self):
+        return self.node_val['next'] == 0
+
+    def next(self):
+        if not self.null():
+            self.node_val = self.node_val['next'].dereference()
+
+    def previous(self):
+        if not self.null():
+            self.node_val = self.node_val['previous'].dereference()
+
+    def cast(self, typename):
+        if not self.null():
+            nodetype = gdb.lookup_type(typename)
+            return self.node_val.cast(nodetype)
+        return None
+
+class control:
+    """Manage the Chain_Control."""
+
+    def __init__(self, ctrl):
+        self.ctrl = ctrl
+
+    def first(self):
+        return node(self.ctrl['first'].dereference())
+
+    def last(self):
+        return node(self.ctrl['first'])