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

code/lib/bitmap.h

@@ -0,0 +1,59 @@
+// bitmap.h 
+//	Data structures defining a bitmap -- an array of bits each of which
+//	can be either on or off.
+//
+//	Represented as an array of unsigned integers, on which we do
+//	modulo arithmetic to find the bit we are interested in.
+//
+//	The bitmap can be parameterized with with the number of bits being 
+//	managed.
+//
+// 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 BITMAP_H
+#define BITMAP_H
+
+#include "copyright.h"
+#include "utility.h"
+
+// Definitions helpful for representing a bitmap as an array of integers
+const int BitsInByte =	8;
+const int BitsInWord = sizeof(unsigned int) * BitsInByte;
+
+// The following class defines a "bitmap" -- an array of bits,
+// each of which can be independently set, cleared, and tested.
+//
+// Most useful for managing the allocation of the elements of an array --
+// for instance, disk sectors, or main memory pages.
+// Each bit represents whether the corresponding sector or page is
+// in use or free.
+
+class Bitmap {
+  public:
+    Bitmap(int numItems);	// Initialize a bitmap, with "numItems" bits
+				// initially, all bits are cleared.
+    ~Bitmap();			// De-allocate bitmap
+    
+    void Mark(int which);   	// Set the "nth" bit
+    void Clear(int which);  	// Clear the "nth" bit
+    bool Test(int which) const;	// Is the "nth" bit set?
+    int FindAndSet();         // Return the # of a clear bit, and as a side
+				// effect, set the bit. 
+				// If no bits are clear, return -1.
+    int NumClear() const;	// Return the number of clear bits
+
+    void Print() const;		// Print contents of bitmap
+    void SelfTest();		// Test whether bitmap is working
+    
+  protected:
+    int numBits;		// number of bits in the bitmap
+    int numWords;		// number of words of bitmap storage
+				// (rounded up if numBits is not a
+				//  multiple of the number of bits in
+				//  a word)
+    unsigned int *map;		// bit storage
+};
+
+#endif // BITMAP_H