added code to _Thread_Clear_state to check if the state was not currently set.

1 files changed, 19 insertions, 13 deletions

diff --git a/cpukit/score/src/thread.c b/cpukit/score/src/thread.c
index 868407b3cd..5ca29b27b9 100644
--- a/cpukit/score/src/thread.c
+++ b/cpukit/score/src/thread.c
@@ -718,32 +718,38 @@ void _Thread_Ready(
  *    select heir
  */
 
+
 void _Thread_Clear_state(
   Thread_Control *the_thread,
   States_Control  state
 )
 {
-  ISR_Level level;
+  ISR_Level       level;
+  States_Control  current_state;
 
   _ISR_Disable( level );
-    the_thread->current_state =
-      _States_Clear( state, the_thread->current_state );
+    current_state = the_thread->current_state;
+    
+    if ( current_state & state ) {
+      current_state = 
+      the_thread->current_state = _States_Clear( state, current_state );
 
-    if ( _States_Is_ready( the_thread->current_state ) ) {
+      if ( _States_Is_ready( current_state ) ) {
 
-      _Priority_Add_to_bit_map( &the_thread->Priority_map );
+        _Priority_Add_to_bit_map( &the_thread->Priority_map );
 
-      _Chain_Append_unprotected( the_thread->ready, &the_thread->Object.Node );
+        _Chain_Append_unprotected(the_thread->ready, &the_thread->Object.Node);
 
-      _ISR_Flash( level );
+        _ISR_Flash( level );
 
-      if ( the_thread->current_priority < _Thread_Heir->current_priority ) {
-        _Thread_Heir = the_thread;
-        if ( _Thread_Executing->is_preemptible ||
-             the_thread->current_priority == 0 )
-          _Context_Switch_necessary = TRUE;
+        if ( the_thread->current_priority < _Thread_Heir->current_priority ) {
+          _Thread_Heir = the_thread;
+          if ( _Thread_Executing->is_preemptible ||
+               the_thread->current_priority == 0 )
+            _Context_Switch_necessary = TRUE;
+        }
       }
-    }
+  }
   _ISR_Enable( level );
 }