--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Scheduler.cbc	Thu Jan 14 15:08:06 2010 +0900
@@ -0,0 +1,89 @@
+#include "Debug.h"
+#include "Scheduler.h"
+
+typedef struct _Scheduler {
+	TaskQueue newTaskQ;
+	TaskQUeue finishTaskQ;
+	SchedTask taskp;	/* previous task. */
+	SchedTask taskc;	/* current task. */
+	SchedTask taskn;	/* next task. */
+
+	__code (*read)(struct _Scheduler*);
+	__code (*exec)(struct _Scheduler*);
+	__code (*write)(struct _Scheduler*);
+} Scheduler;
+
+__code
+schedulerStart()
+{
+	sched->taskp = NoTask;
+	sched->taskc = NoTask;
+	goto getNewTask();
+}
+
+__code
+loop(Scheduler *sched)
+{
+	sched->taskp = sched->taskc;
+	sched->taskc = sched->taskn;
+	sched->taskn = NULL;
+	if (/*have no task*/) {  /* sched->taskp==NOP&&sched->taskp==NOP  */
+		// state patternできるか？
+		goto waitNewTask(sched);
+	} else {
+		goto getNewTask(sched);
+	}
+}
+
+__code
+getNewTask(Scheduler *sched)
+{
+	/* we should always have 3 tasks; previous, current and next.  */
+	sched->taskn = queuePoll(newTaskQ);
+	if (!sched->taskn) {
+		sched->taskn = NoTask; /* default task which do nothing.  */
+	}
+	goto sched->read(sched);
+}
+
+__code
+waitNewTask(Scheduler *sched)
+{
+	/* wait new task.  */
+	sched->taskn = queueTake(newTaskQ);
+	goto sched->read(sched);
+}
+
+
+
+/* depending implementation.  */
+__code
+read(Scheduler *sched)
+{
+	/* start DMA for readbuffer of a next task.  */
+	/* wait for finishing DMA for readbuffer of a current task.  */
+	goto sched->exec(sched);
+}
+__code
+execute(Scheduler *sched)
+{
+	/* execute current task.  */
+	goto sched->write(sched);
+}
+__code
+write(Scheduler *sched)
+{
+	/* wait for finishing DMA for writebuffer of a previous task.  */
+	/* start DMA for writebuffer of a current task.  */
+	goto finishTask(sched);
+}
+
+__code
+finishTask(Scheduler *sched)
+{
+	queueOffer(sched->finishTaskQ, sched->taskp);
+	goto loop(sched);
+}
+
+
+