CSc 3210 Name:
Computer Organization and Programming
Fall 1998
Solutions to Quiz #1 (9 September 1998, Wednesday)

1.
Consider the Floating Point Notation in which 1 bit is used for Sign, 2 bits for Exponent and 2 bits for Mantissa. Fill in the real number being represented by the following bit patterns:
SIGN EXPONENT MANTISSA REAL NUMBER
0 00 00 +0.0000
0 00 01 +0.0625
0 00 10 +0.1250
0 00 11 +0.1875
0 01 00 +0.0000
0 01 01 +0.1250
0 01 10 +0.2500
0 01 11 +0.3750
0 10 00 +0.0000
0 10 01 +0.2500
0 10 10 +0.5000
0 10 11 +0.7500
0 11 00 +0.0000
0 11 01 +0.5000
0 11 10 +1.0000
0 11 11 +1.5000

2.
Suppose a machine stores real numbers in floating point notation with 1 bit for sign, 4 bits for exponent and 6 bits for mantissa.

(a)
What is the largest number that can be represented in this notation?

Answer: +126
(b)
What is the smallest non-zero positive number that can be represented in this notation?

Answer: 2-14 = 0.000061035156

3.
Convert the following IEEE floating-point number to decimal notation:
1 10001111 01011101101010000000000



Answer: -89512



Dr. Raj Sunderraman
9/9/1998