GATE CSE
First time here? Checkout the FAQ!
x
0 votes
71 views

I am getting answer as 9 , the given answer is 8.

asked in CO & Architecture by Junior (667 points)   | 71 views
Ans should be 8 itself, 4 instruction 5 stages Ist instructruction will be completed at 5th cycle, then 6,7 and 8, no stall will be there as all hazards will be removed by forwarding.
Ahh, sorry my mistake.

So basically even if OF stage for second instruction takes wrong value they will be corrected by operand forwarding !
Actually OF stage here is 3 so by that time we will be having correct input. This isn't the case where Ist it is fed wrong input and forwarding will update it. this isn't possible at all. thing is if we are getting correct input by OF stage then proceed otherwise stall. Like if OF is at 2nd stage then we have to insert a 1 stall.
Answer will be 8 ,as here operand forwarding is used
yup, 8 cycles.

But shrestha, 

Is my above reason correct ? - 

So basically even if OF stage for second instruction takes wrong value they will be corrected by operand forwarding 

yes, you are right.

1 Answer

–1 vote

 

  1 2 3 4 5 6 7 8
I1 IF ID OF EX WB      
I2   IF ID OF EX WB    
I3     IF ID OF EX WB  
I4       IF ID OF EX WB

 

 

 

 

 

in this question instruction I1 perform the addition operation and result store in ALU in clock cycle 3 and next instruction I2 use the result which is store by instruction I1 using operand forwarding !

hence the total clock cycle is 8.

answered ago by (75 points)  
edited ago by

Related questions

Top Users Jan 2017
  1. Debashish Deka

    8978 Points

  2. sudsho

    5326 Points

  3. Habibkhan

    4798 Points

  4. Bikram

    4676 Points

  5. Vijay Thakur

    4496 Points

  6. saurabh rai

    4222 Points

  7. Arjun

    4216 Points

  8. Sushant Gokhale

    3834 Points

  9. santhoshdevulapally

    3808 Points

  10. Kapil

    3736 Points

Monthly Topper: Rs. 500 gift card

19,229 questions
24,123 answers
53,256 comments
20,322 users