Howard University

Department of Electrical & Computer Engineering

 

EECE 200 � Introduction to Computer Engineering

�����������������������������������������������������������

Homework 3

 

 

 

2.8) a.What is the largest positive number one can represent in an 8-bit 2�s complement code? Write your result in binary and decimal.

 

����� b. What is the greatest magnitude negative number one can represent in an 8-bit 2�s complement code? Write your result in binary and decimal.

 

���� c.What is the largest positive number one can represent in an n-bit 2�s complement code?

 

���� d. . What is the greatest magnitude negative number one can represent in an n-bit 2�s complement code?

 

2.11) Convert these decimal numbers to�� 8-bit 2�s complement binary numbers.

 

���� a. 102

���� b.�� 64

���� c. ��33

���� d. 127

 

 

2.13) Without changing their values, convert the following 2�s complement binary numbers into 8-bit 2�s complement numbers.

 

���� a.� 1010

���� b.� 011001

���� c.� 1111111000

���� d.� 01

 

2.22) Create two 16-bit 2�s complement integers such that their sum causes an overflow.

 

2.30) Compute the following.� Write your results in binary.

 

���� a.� 01010111 AND 11010111

���� b.� 101 AND 110

���� c.� 11100000 AND 10110100

���� d.� 00011111 AND 10110100

���� e.� (0011 AND 0110) AND 1101

f.� 0011 AND (0110 AND 1101)

 

2.36) Refer to Example 2.11 in the textbook for the following questions.

���� a.� What mask value and what operation would one use to indicate that machine 2 is busy?

���� b.� What mask value and what operation would one use to indicate that machines 2� and 6 are busy? (Note: This can be done with one operation.)

���� c.� What mask value and what operation would one use to indicate that all machines���������������� are busy?

���� d.� What mask value and what operation would one use to indicate that all machines�� ��������������are idle?

���� e.� Develop a procedure to isolate the status bit of machine 2 as the sign bit.� For example, if the BUSYNESS patter is 01011100, then the output of this procedure is 10000000.� If the BUSYNESS pattern is 01110011, then the output is 00000000. In general, if the BUSYNESS pattern is:

b7,b6,b5,b4,b3,b2,b1,b0

the output is:

b2,0,0,0,0,0,0,0.

Hint: What happens when you ADD a bit pattern to itself?

 

 

 

2.49)� Perform the following additions.� The corresponding 16-bit binary numbers are in 2�s complement notatin. Provide yout answers in hexadecimal.

���� a.� x025B + x26DE

���� b.� x7D96 + xF0A0

���� c.� xA397 + xA35D

���� d.� x7D96 + x7412

���� e.� What else can you say about the numbers to parts c and d?

 

 

2.50) Perform the following logical operations.� Express your answers in hexadecimal notation.

���� a.� x5478 AND xFDEA

���� b.� xABCD OR x1234

���� c.� NOT( ( NOT(xDEFA) ) AND ( NOT(xFFFF) )� )

���� d.� x00FF XOR x325C

 

2.51) What is the hexadecimal representation of the following numbers?

���� a.� 25,675

���� b.� 675.625 (that is 675 and 5/8ths), in the IEEE floating point standard

���� c.� The ASCII string: Hello

2.54) Fill in the truth table for the equation given.� The first line is don as an example.

 

Q1 = NOT (A AND B)

Q2 = NOT ( NOT(A) AND NOT(B) )

A

B

Q1

Q2

0

0

1

0