n instruction set of a processor has 125 signals which can be divided into 5 groups of mutually exclusive signals as follows:
Group 1 : 20 signals, Group 2 : 70 signals, Group 3 : 2 signals, Group 4 : 10 signals, Group 5 : 23 signals.
How many bits of the control words can be saved by using vertical microprogramming over horizontal microprogramming?
(A) 0
(B) 103
(C) 22
(D) 55
Answer: (B)
Explanation:
In horizontal microprogramming, each control signal is represented by one bit in the microinstruction.
Therefore, total number of bits of the control words required in Horizontal microprogramming :
= 20 + 70 + 2 + 10 + 23 = 125 bits
In vertical microprogramming, \’n\’ control signals encoded into log2 n bits.
group 1 : log2 20 = 5 bits
group 2 : log2 70 = 7 bits
group 3 : log2 2 = 1 bits
group 4 : log2 10 = 4 bits
group 5 : log2 23 = 5 bits
Total number of bits required in vertical microprogramming = 5 + 7 + 1 + 4 + 5 = 22 bits
So, number of bits saved= 125 – 22 = 103 bits.
Thus, option (B) is correct.
Please comment below if you find anything wrong in the above post.
Quiz of this Question
Share your thoughts in the comments
Please Login to comment...