Handout

kernel/thread/dispatcher.h

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+// vim: set noet ts=4 sw=4:
+
+/*! \file
+ *  \brief \ref Dispatcher for \ref Thread threads
+ */
+#pragma once
+#include "../thread/thread.h"
+#include "../types.h"
+
+/*! \brief The dispatcher dispatches threads and puts the scheduler's
+ *  decisions into action.
+ *  \ingroup thread
+ *
+ *  The dispatcher manages the life pointer that refers to the currently
+ *  active thread and performs the actual switching of processes.
+ *  For single-core systems, a single life pointer is sufficient, as only a
+ *  single thread can be active at any one time. On multi-core systems,
+ *  every CPU core needs its own life pointer.
+ */
+class Dispatcher {
+	Thread* life;
+
+	/*! \brief set the currently active thread
+	 *  \param thread active Thread
+	 */
+	void setActive(Thread* thread) { life = thread; }
+
+   public:
+	/*! \brief constructor
+	 *
+	 */
+	Dispatcher();
+
+	/*! \brief Returns the thread running on the CPU core calling this method
+	 *
+	 */
+	Thread* active() const;
+
+	/*! \brief This method stores first as life pointer for this CPU core and
+	 *  triggers the execution of first. Only to be used for the first thread
+	 *  running on a CPU.
+	 *  \param first First thread to be executed on this CPU core.
+	 *
+	 */
+	void go(Thread* first);
+
+	/*! \brief Updates the life pointer to next and issues a thread change from
+	 *  the old to the new life pointer.
+	 *  \param next Next thread to be executed.
+	 *
+	 */
+	void dispatch(Thread* next);
+};