CSC 221: Computer Organization, Spring 2009

Assignments

Friday, February 6:

Chapter 2, Exercises 2, 3, 8, 16, and 18

Wednesday, February 18:

Chapter 3, Exercises 20, 23, 25, 27, 36, 39, 48, and 49

Wednesday, February 25:

Chapter 4, Exercises 4, 6, 9, and 14

Wednesday, March 18:

Chapter 5, Exercises 9, 12, 16, 19, 24, and 30

Monday, March 30:

Exam 1 Make-up Project: Write a program which will read an 8-bit binary number and print out the ten interpretations from problem 3 of the exam. Here are two examples of running it:

Enter binary (8 bits): 01010001
Unsigned int: 81
Hexadecimal: 51
Octal: 121
Two's complement: 81
Sign magnitude: 81
One's complement: 81
Excess-127: -46
ASCII: Q
Pep/8: CHARO direct
Floating-point: 4.25

Enter binary (8 bits): 10001000
Unsigned int: 136
Hexadecimal: 88
Octal: 210
Two's complement: -120
Sign magnitude: -8
One's complement: -119
Excess-127: 9
ASCII: N/A
Pep/8: SUBX immediate
Floating-point: -0.125
			

There is a folder in the public directory of the I: drive for this course containing a Windows executable of the demonstration version which produced the above output, along with some starter C++ code which you may use. The grade for this project will be 10% for each correct interpretation, applied as a replacement for whatever grade you received on the exam (that is, if you correctly do 7 of the interpretations, I will give you 70% on the exam, if that is larger than your actual score). You may talk to other people about this project, but all code you submit must be your own (other than my starter code).

Friday, April 10:

Chapter 6, Exercises 4, 13, 15, and 18

Monday, April 20:

Programming Project: Write and test a program in Pep/8 assembly language to do the following:

• Read a list of at most 100 positive numbers from the input, terminated with 0 if there are fewer than 100;
• Sort the numbers;
• Print the sorted list of numbers on the output.

To get a score of 80 points out of 100, your program must have the above behavior. To qualify for an additional 10 points each, your program should do the following:

• The main program should be structured as a series of calls to subprograms: read an array of numbers, sort an array, print an array;
• The sorting algorithm should be O(N log N) instead of O(N^2) -- I suggest Quicksort. Here is one version in C++:

        void swap(int &a, int &b)
        {
            int temp = a;
            a = b;
            b = temp;
        }
  
        int partition(int a[], int left, int right)
        {
            int pivot = a[left];
            int i = left;
  
            for (int j = left + 1; j <= right; j++) {
                if (a[j] < pivot) {
                    i++;
                    swap(a[j], a[i]);
                }
            }
  
            swap(a[left], a[i]);
            return i;
        }
  
        // Sort array elements a[left] through a[right], inclusive.
        void quicksort(int a[], int left, int right)
        {
            if (right <= left) return;
            int i = partition(a, left, right);
            quicksort(a, left, i - 1);
            quicksort(a, i + 1, right);
        }

I strongly recommend that you write the program in C++ first, then translate your working (i.e., tested and debugged) C++ program into Pep/8 assembly language, and then test it again on the Pep/8 simulator. Your testing should be thorough enough to convince yourself that the translation has been done correctly and that the program has no bugs. You may work on this project in pairs; make sure that your name(s) are given in comments at the top of the source code. When you are finished, either email the Pep/8 source code file to me, or put it in your folder on the I: drive and email me the directory and file name.

Wednesday, April 22:

Chapter 10, Exercises (15g, 16g, 17g, 21e, 22e, 23e, 27e, 28e), (31e, 32e), 33e, 36e, and 44

Wednesday, May 6:

Because of the timing of this assignment and the final, I am making it optional. If you would like to complete it and submit it for grading, I will consider it as extra credit (but note that I tend not to give much partial credit on extra credit problems, so please don't submit unless you have complete solutions).
As practice for the exam, do Chapter 11, Exercises 8(b, c, e, and h) and 11.
As a further exercise, do Chapter 11, Exercise 16(a), except have 8 states (000 through 111) instead of 4, and build the circuit in Logisim. Incorporate the 7-segment decoder from class in the circuit so it will display numbers from 0 to 7 when counting. Save the .circ file in your folder on the I: drive and email me the file name (or just attach the file).

DePauw University, Computer Science Department, Spring 2009
Maintained by Brian Howard (bhoward@depauw.edu). Last updated