3-4 Arithmetic Circuits and ALUs

Question 1

When using a series of chained full adders (one pictured) for adding two integers together, the value of the carry in for the least significant integer column would be:

Answer 1

0

Question 2

A shifter can shift bits one to the left, but cannot shift bits one to the right.

Answer 2

False

Question 3

Which of the following statements is true about the shifter pictured below?

Answer 3

An unsigned shifter is pictured. We know the shifter is for unsigned integers because the shifter always inserts a 0 for the most significant bit for right shifts instead of inserting the correct sign bit.

Question 4

A 1 bit ALU is pictured. Which function is selected by the decoder, and what is the value of the output bits?

F0=1

F1=1

ENA=1

ENB=0

A=0

B=1

INVA=0

Carry_In=1

Answer 4

ADD, Output=1, CarryOut=0

Question 5

A 1 bit ALU is pictured. Which function is selected by the decoder, and what is the value of the output bits?

F0=0

F1=1

ENA=0

ENB=1

A=0

B=0

INVA=1

Carry_In=0

Answer 5

OR, Output=1