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need Help Assume we are using the simple model for floating-point representation

ID: 3915085 • Letter: N

Question

need Help

Assume we are using the simple model for floating-point representation as given in this book (the representation uses a 14-bit format, 5 bits for the exponent with a bias of 15, a normalized mantissa of 8 bits, and a single sign bit for the number):
a) Show how the computer would represent the numbers 100.0 and 0.25 using this
floating-point format.
b) Show how the computer would add the two floating-point numbers in part a by
changing one of the numbers so they are both expressed using the same power of 2.
c) Show how the computer would represent the sum in part b using the given floating point representation. What decimal value for the sum is the computer actually storing?

   a.1) 100.0 = _ _ _ _ _ _ _ _ _ _ _ _ _ _

   a.2) 0.25 = _ _ _ _ _ _ _ _ _ _ _ _ _ _

   b) Adding part a) we get _________________ x 27

   c) The sum from part b) in the given floating point notation is _ _ _ _ _ _ _ _ _ _ _ _ _ _

which is equal to ____  _____(base 10)

Explanation / Answer

a.1)100

Bias= 15

100 in binary = 1100100 = (0.1100100)*2^(7)

Exponent = 7+bias= 7+15 = 22

22 in binary 10110

Floating point 14 bit layout

Sign bit( 1 bit )

Exponent( 5 bits )

Mantissa( 8 bits )

0

10110

11001000

Floating point representation is

0 10110 11001000

a.2) 0.25

Bias= 15

0.25 in binary = 0.01 = (0.1)*2^(-1)

Exponent = -1+bias= -1+15 = 14

14 in binary 1110

Floating point 14 bit layout

Sign bit( 1 bit )

Exponent( 5 bits )

Mantissa( 8 bits )

0

01110

10000000

Floating point representation is

0 01110 10000000

Add both numbers,

100+0.25 = 100.25

1100100. 01 = 0.110010001*2^(7)

7+bias= 7+15=22

Floating point 14 bit layout

Sign bit( 1 bit )

Exponent( 5 bits )

Mantissa( 8 bits )

1

10110

11001000

Sign bit( 1 bit )

Exponent( 5 bits )

Mantissa( 8 bits )

0

10110

11001000