Made Easy Test Series:Microprogramming

Question

A hypothetical cpu supports $300$ instructions.each instruction takes $5$ cycle to accomplish the execution. the control unit is designed using vertical programming which has $130$ control signals $,64$ flags and $12$ branch conditions .$X$ and $Y$ represent the number of bits required for control address register$(CAR)$ and control data register$(CDR)$ respectively.value of $X+Y$ is ______?

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How to work with branch condition in micro programming :(

Comments

Gate Fever

what you are not getting in their solution ??

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now got it

actually they have written min 3 cycles and max 5  cycles and this was asked in another ques, so i thought they have given wrong answer

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x+y = 30 + 11 = 41

Answer 1

Total micro operation which have to be stored in control memory is = 300*5 =1500

Number of bits are required to address one of the micro operation from control memory is log(1500) = 11 bits (CAR)

Number of bits are required CMDR (Control memory data register) = Flag(6) + branch Condition(4) + Control signals(8) + next micro operation address(11) = 29 bits

therefore CAR+CDR =40 bits

Comments

11 + 29= 40

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Agreed.

Answer 2

40 bits

x=11   as 300 instructions takes 5 cycles each so total references 300*5=1500
           x=log1500=11
y=29

         y=log12+log130 (as given vertical)+log64+log1500