[F3CS] binary shift

Bit Shifting

Objectives

● Understand what bit shifting is and how it is done

● Understand what shifting to right / left does to the

number

● A binary shift moves all the bits in a binary number a

certain number of positions to the left or right

● This is a fast way of multiplying or dividing the

number by the power of 2

Shifting to the left

Shifting the a byte to the left = multiplying number by 2
By doing so the left most bit (most significant bit) will be
lost

Shifting to the right

Shifting the a byte to the left = multiplying number by 2
By doing so the left most bit (most significant bit) will be
lost

Open Ended

What do we use binary shifting for?

Multiple Choice

What does binary shifting to the right by 1 do?

• Multiply by 2

• Multiply by 4

• Divide by 2

• Divide by 4

Multiple Choice

To perform multiplication, you must shift the number to the

• Left

• Right

• Up

• Down

0110 1110 << 2 = 1011 1000
0110 1110 >> 2 = 0001 1011

Shifting to the left:
one bit = x2
Two bit = x22 = x4
Three bit = x23 = x8

Shifting to the right:
One bit = /2
Two bit = /22 = /4
Three bit = /23 = /8

0011 1100 = 60
0011 1100 << 1 = 0111 1000 = 120
0011 1100 << 2 = 1111 0000 = 240

0011 1100 = 60
0011 1100 >> 1 = 0001 1110 = 30
0011 1100 >> 2 = 0000 1111 = 15

Multiple Choice

A left shift of 2 will produce the following results:

• 4 to 16

• 16 to 4

• 4 to 8

• 8 to 4