1 files changed, 105 insertions, 0 deletions
diff --git a/cpukit/score/src/threadtickletimeslice.c b/cpukit/score/src/threadtickletimeslice.c
new file mode 100644
index 0000000000..50ded7f6a7
--- /dev/null
+++ b/cpukit/score/src/threadtickletimeslice.c
@@ -0,0 +1,105 @@
+/*
+ *  Thread Handler
+ *
+ *
+ *  COPYRIGHT (c) 1989-2009.
+ *  On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/score/apiext.h>
+#include <rtems/score/context.h>
+#include <rtems/score/interr.h>
+#include <rtems/score/isr.h>
+#include <rtems/score/object.h>
+#include <rtems/score/priority.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/states.h>
+#include <rtems/score/sysstate.h>
+#include <rtems/score/thread.h>
+#include <rtems/score/threadq.h>
+#include <rtems/score/userext.h>
+#include <rtems/score/wkspace.h>
+
+/*PAGE
+ *
+ *  _Thread_Tickle_timeslice
+ *
+ *  This scheduler routine determines if timeslicing is enabled
+ *  for the currently executing thread and, if so, updates the
+ *  timeslice count and checks for timeslice expiration.
+ *
+ *  Input parameters:   NONE
+ *
+ *  Output parameters:  NONE
+ */
+
+void _Thread_Tickle_timeslice( void )
+{
+  Thread_Control *executing;
+
+  executing = _Thread_Executing;
+
+  #ifdef __RTEMS_USE_TICKS_FOR_STATISTICS__
+    /*
+     *  Increment the number of ticks this thread has been executing
+     */
+    executing->cpu_time_used++;
+  #endif
+
+  /*
+   *  If the thread is not preemptible or is not ready, then
+   *  just return.
+   */
+
+  if ( !executing->is_preemptible )
+    return;
+
+  if ( !_States_Is_ready( executing->current_state ) )
+    return;
+
+  /*
+   *  The cpu budget algorithm determines what happens next.
+   */
+
+  switch ( executing->budget_algorithm ) {
+    case THREAD_CPU_BUDGET_ALGORITHM_NONE:
+      break;
+
+    case THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE:
+    #if defined(RTEMS_SCORE_THREAD_ENABLE_EXHAUST_TIMESLICE)
+      case THREAD_CPU_BUDGET_ALGORITHM_EXHAUST_TIMESLICE:
+    #endif
+      if ( (int)(--executing->cpu_time_budget) <= 0 ) {
+
+        /*
+         *  A yield performs the ready chain mechanics needed when
+         *  resetting a timeslice.  If no other thread's are ready
+         *  at the priority of the currently executing thread, then the
+         *  executing thread's timeslice is reset.  Otherwise, the
+         *  currently executing thread is placed at the rear of the
+         *  FIFO for this priority and a new heir is selected.
+         */
+        _Scheduler_Yield( );
+        executing->cpu_time_budget = _Thread_Ticks_per_timeslice;
+      }
+      break;
+
+    #if defined(RTEMS_SCORE_THREAD_ENABLE_SCHEDULER_CALLOUT)
+      case THREAD_CPU_BUDGET_ALGORITHM_CALLOUT:
+	if ( --executing->cpu_time_budget == 0 )
+	  (*executing->budget_callout)( executing );
+	break;
+    #endif
+  }
+}