1 files changed, 40 insertions, 0 deletions
diff --git a/cpukit/score/src/scheduleredfprioritycompare.c b/cpukit/score/src/scheduleredfprioritycompare.c
new file mode 100644
index 0000000000..324e44af37
--- /dev/null
+++ b/cpukit/score/src/scheduleredfprioritycompare.c
@@ -0,0 +1,40 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 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/config.h>
+#include <rtems/score/scheduleredf.h>
+
+int _Scheduler_EDF_Priority_compare (
+  Priority_Control p1,
+  Priority_Control p2
+)
+{
+  Watchdog_Interval time = _Watchdog_Ticks_since_boot;
+
+  /*
+   * Reorder priorities to separate deadline driven and background tasks.
+   *
+   * The background tasks have p1 or p2 > SCHEDULER_EDF_PRIO_MSB.
+   * The deadline driven tasks need to have subtracted current time in order
+   * to see which deadline is closer wrt. current time.
+   */
+  if (!(p1 & SCHEDULER_EDF_PRIO_MSB))
+    p1 = (p1 - time) & ~SCHEDULER_EDF_PRIO_MSB;
+  if (!(p2 & SCHEDULER_EDF_PRIO_MSB))
+    p2 = (p2 - time) & ~SCHEDULER_EDF_PRIO_MSB;
+
+  return ((p1<p2) - (p1>p2));
+}