Pipelining Problem

Question

How to slove this type of problems? How to understand the problem?Please help me out. Given answer is 31

Answer 1

 While fetching, 1 word will be fetched which take two cycles and while decoding phase remaining instruction is fetched which all will take 2cycle.

for ex:

  I1 :

IF : 1 word is fetch which require 2 cycle

ID: remaining 2 words are fetched which require 2cycle each =2*2=4

EX: Move instruction ,  nothing to execute = 0 cycle

WB: requires 2 cycle in every instruction

do similarly for other also.

Instruction	IF	ID	EX	WB
I1	2	4	0	2
I2	2	0	2	2
I3	2	4	0	2
I4	2	4	0	2

Total cycle required to execute the program is 31 cycles.

Comments

Please elaborate!

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Sir, I am not getting 31 cycles by your approach, on drawing the instruction clock table

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for 11 :

IF : 1 word is fetch which require 2 cycle

ID: remaining 2 words are fetched which require 2cycle each =2*2=4

EX: Move instruction ,  nothing to execute = 0 cycle

WB: requires 2 cycle in every instruction

do similarly for other also.

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In case of Load and Store, EX will be 0 , right?