Chapter 2

Question 1

How is the number -x represented using 2’s complement?

Answer 1

-x = 2ⁿ-x

(Where n = the number of bits used to represent numbers).

(( in the picture: n = 4 ))

Question 2

What is the algorithm for adding 1 to a binary number?

What is the algorithm for subtracting 1 from a binary number?

Answer 2

Move from right to left.

To add 1:

Flip all the digits until you have changed a 0 to a 1.

To subtract 1:

Flip all the digits until you have changed a 1 to a 0.

Question 3

What is the binary representation of Not(x)?

Answer 3

Not(x) = -x-1

Question 4

How do the ALU’s control bits control what the ALU computes?

Answer 4

Question 5

Answer 5