1 files changed, 91 insertions, 0 deletions
diff --git a/cpukit/score/src/threadresettimeslice.c b/cpukit/score/src/threadresettimeslice.c
new file mode 100644
index 0000000000..4697ef74de
--- /dev/null
+++ b/cpukit/score/src/threadresettimeslice.c
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup RTEMSScoreThread
+ *
+ * @brief This source file contains the definition of
+ *   ::_Thread_CPU_budget_reset_timeslice and the implementation of
+ *   _Thread_CPU_budget_consume_and_yield() and
+ *   _Thread_CPU_budget_set_to_ticks_per_timeslice().
+ */
+
+/*
+ * Copyright (C) 2021 embedded brains GmbH & Co. KG
+ * Copyright (C) 2010 Gedare Bloom  <gedare@rtems.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/score/threadcpubudget.h>
+#include <rtems/score/threadimpl.h>
+#include <rtems/score/statesimpl.h>
+#include <rtems/score/watchdogticks.h>
+
+void _Thread_CPU_budget_consume_and_yield( Thread_Control *the_thread )
+{
+  uint32_t budget_available;
+
+  if ( !the_thread->is_preemptible ) {
+    return;
+  }
+
+  if ( !_States_Is_ready( the_thread->current_state ) ) {
+    return;
+  }
+
+  budget_available = the_thread->CPU_budget.available;
+
+  if ( budget_available == 1 ) {
+    the_thread->CPU_budget.available = _Watchdog_Ticks_per_timeslice;
+
+    /*
+     *  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.
+     */
+    _Thread_Yield( the_thread );
+  } else {
+    the_thread->CPU_budget.available = budget_available - 1;
+  }
+}
+
+void _Thread_CPU_budget_set_to_ticks_per_timeslice(
+  Thread_Control *the_thread
+)
+{
+  the_thread->CPU_budget.available = _Watchdog_Ticks_per_timeslice;
+}
+
+const Thread_CPU_budget_operations _Thread_CPU_budget_reset_timeslice = {
+  .at_tick = _Thread_CPU_budget_consume_and_yield,
+  .at_context_switch = _Thread_CPU_budget_set_to_ticks_per_timeslice,
+  .initialize = _Thread_CPU_budget_set_to_ticks_per_timeslice
+};