Answer to Question #123670 in C++ for desmond

Question

Compute -ABE16-DF416 using 15’s complement [4 marks]
b) Compute the 3658-3458 in 2’s complement signed magnitude form.

Answer 1

(i)

To compute: A B E- D F 4 with base 16 using 15’s compliment

As we know in 15’s compliment we have to subtract the given hexadecimal digit with 15.

Therefore,  

  15 15 15  => 15 15 15

 - A  B  E  => 10 11 14

 _________

  5   4   1

 __________  => is the 15’s compliments

• 15’s compliment for D F 4

Similarly,

          15 15 15

- D  F  4

________

 2  0  B  =>15’s compliment

Now to compute ABE-DF4

 (A-B) of 15’s compliment is

A+(15’s compliment of B)

=> ABE+(20B)

=> 10 11 14+(2 0 11)

=> 12 11 25

=> C B 25 is the final answer

To compute 3658-3458 in 2’s compliment signed magnitude form:

2’s compliment of 3658 =

1’s compliment of 3658 +1

0011011001011000 => binary form  

1100100110100111 => 1’s compliment 

+                1 ______________________

 1100100110101000  =>  2’s compliment   

2’s compliment of 3458

similarly,

 1100101110101000 2’s compliment

Now computing the 3658-3458

(A-B) in 2’s compliment =

A+(2’s compliment of B)

 0011011001011000+

(1100101110101000)

 1111111000000000 is the answer.