init: init nachos hw01, should pass jenkins os_group_20_hw job but fail on os_group_20_ta job

code/threads/alarm.h

@@ -0,0 +1,42 @@
+// alarm.h 
+//	Data structures for a software alarm clock.
+//
+//	We make use of a hardware timer device, that generates
+//	an interrupt every X time ticks (on real systems, X is
+//	usually between 0.25 - 10 milliseconds).
+//
+//	From this, we provide the ability for a thread to be
+//	woken up after a delay; we also provide time-slicing.
+//
+//	NOTE: this abstraction is not completely implemented.
+//
+// Copyright (c) 1992-1996 The Regents of the University of California.
+// All rights reserved.  See copyright.h for copyright notice and limitation 
+// of liability and disclaimer of warranty provisions.
+
+#ifndef ALARM_H
+#define ALARM_H
+
+#include "copyright.h"
+#include "utility.h"
+#include "callback.h"
+#include "timer.h"
+
+// The following class defines a software alarm clock. 
+class Alarm : public CallBackObj {
+  public:
+    Alarm(bool doRandomYield);	// Initialize the timer, and callback 
+				// to "toCall" every time slice.
+    ~Alarm() { delete timer; }
+    
+    void WaitUntil(int x);	// suspend execution until time > now + x
+                                // this method is not yet implemented
+
+  private:
+    Timer *timer;		// the hardware timer device
+
+    void CallBack();		// called when the hardware
+				// timer generates an interrupt
+};
+
+#endif // ALARM_H