2002-04-08 Chris Johns <ccj@acm.org>

* Per PR142, make task switch extension its own list.
	* include/rtems/score/userext.h: Reflect above by adding
	User_extensions_Switch_control and adding it to User_extenions_Control.
	* inline/rtems/score/userext.inl: Allocate all memory in one chunk
	to minimize overhead.  Address processing dedicated switch chain.

c/src/exec/score/include/rtems/score/userext.h

@@ -91,11 +91,24 @@ typedef struct {
 }   User_extensions_Table;
 
 /*
- *  The following is used to manage each user extension set.
+ *  The following is used to manage the list of switch handlers.
  */
 
 typedef struct {
   Chain_Node                              Node;
+  User_extensions_thread_switch_extension thread_switch;
+}   User_extensions_Switch_control;
+
+/*
+ *  The following is used to manage each user extension set.
+ *  The switch control is part of the extensions control even
+ *  if not used due to the extension not having a switch
+ *  handler.
+ */
+
+typedef struct {
+  Chain_Node                     Node;
+  User_extensions_Switch_control Switch;
   User_extensions_Table          Callouts;
 }   User_extensions_Control;
 
@@ -105,6 +118,13 @@ typedef struct {
 
 SCORE_EXTERN Chain_Control _User_extensions_List;
 
+/*
+ *  The following is used to manage a chain of user extension task
+ *  switch nodes.
+ */
+
+SCORE_EXTERN Chain_Control _User_extensions_Switches_list;
+
 /*
  *  _User_extensions_Thread_create
  *

cpukit/score/include/rtems/score/userext.h

@@ -91,11 +91,24 @@ typedef struct {
 }   User_extensions_Table;
 
 /*
- *  The following is used to manage each user extension set.
+ *  The following is used to manage the list of switch handlers.
  */
 
 typedef struct {
   Chain_Node                              Node;
+  User_extensions_thread_switch_extension thread_switch;
+}   User_extensions_Switch_control;
+
+/*
+ *  The following is used to manage each user extension set.
+ *  The switch control is part of the extensions control even
+ *  if not used due to the extension not having a switch
+ *  handler.
+ */
+
+typedef struct {
+  Chain_Node                     Node;
+  User_extensions_Switch_control Switch;
   User_extensions_Table          Callouts;
 }   User_extensions_Control;
 
@@ -105,6 +118,13 @@ typedef struct {
 
 SCORE_EXTERN Chain_Control _User_extensions_List;
 
+/*
+ *  The following is used to manage a chain of user extension task
+ *  switch nodes.
+ */
+
+SCORE_EXTERN Chain_Control _User_extensions_Switches_list;
+
 /*
  *  _User_extensions_Thread_create
  *