1.4.2 (Binary fractions)

Question 1

What is a fixed point fraction?

Answer 1

• A way of representing a decimal in binary e.g 5.5 = 0101.1000

Question 2

What is the “.” called in a fixed point fraction?

Answer 2

• Binary point

Question 3

What is floating point binary?

Answer 3

• A way of representing a decimal using the least amount of bits
• e.g. 0.001*2^2 = 0.1

Question 4

What is a mantissa?

Answer 4

• A number to be multiplied by an exponent

Question 5

What is an exponent?

Answer 5

• A number representing the power to which a mantissa is to be multiplied by

Question 6

How do you add floating point numbers?

Answer 6

• Make the exponents the same, if increasing the exponent you must decrease the number, and vice versa
• Add the mantissas

Question 7

How do you subtract floating point numbers?

Answer 7

• Make the exponents the same, if increasing the exponent you must decrease the number, and vice versa
• Flip to 2sC
• Add the mantissas

Question 8

What is positive floating point normalisation?

Answer 8

• The sign bit is 0 and the next digit is a 1
• e.g. 0.1101

Question 9

What is negative floating point normalisation?

Answer 9

• The sign bit is 1 and the next digit is a 0
• e.g. 1.0111

Question 10

How do you add floating point numbers?

Answer 10

• Make the exponents the same
• Add the mantissas

Question 11

How do you subtract floating point numbers?

Answer 11

• Make the exponents the same
• Flip second number to 2sC
• Add the mantissas