Microprogrammed control unit 1

Question

Ques:-

Control field of microinstruction contain two groups of control signal group 1 supports none or one of 64 control signals and group 2 supports at most 6 from remaining. What is size of micro operation?

(what is the meaning of "from remaining" here?)

Comments

12?

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pooja solution ??

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ma,am

how you have use hybrid approach vertical + horizontal

in horizontal how can we assign 1 bit ( 1 cs +nop)

its mention from remaining cs we have to select

please correct me in case of wring

Answer 1

One or none = vertical miP = 6 bit
atmost n require horizontal miP = 6 bit
so total 12 bit.

Comments

13 will be the answer ….u need to give 64+1 bit for indicating no signal is active in the group which gives log65 = 7

and rest 6 will be as it is...leading to 13 bits

Answer 2

It means that there are total 64 control signals available in the Control Unit, and there are two groups considered here. One group will have either none or one control signal from the given 64 signals. The other group can have at most 6 control signals from the remaining 63 signals, if the previous group used one signal, or from 64 signals, if the previous group didn't use any signal.

Comments

please correct me in case of wrong

Cs- control signal

 

group 1

one signal from 64 control signal+1 nop

need decoder ->128*7 ->7 bit

group 2

atmost 6

for 1: remaining 63 cs + nop ->decoder 64*6 ->6bit

therefore for 6 control signal to active we need 6 decoders (64*6)

36 bit + 7 bit(group 1) ->43 bit

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Group 1:- 

64 Control signals are there out of which only one or none of them is active therefore number of bits required for decoder is (vertical micropogramming) 6 bits.

Group 2:-

In worst case remaining there will be 63 control signals and condition is atmost 6 control will be active from the remaining therefore (if we will go through horizonal microprogramming we will require 63 or 64 bits ) if we go through vertical microprogramming 6 bits are required for 1 control signal to be active therefore for atmost 6 control signal to be active 6*6 bits(36 bits) require 

6+36=42 bits