Applied Test Series

Question

Consider the following sequence of instructions:

 

LOAD R4, 0(R8)

AND R1, R5, R2

OR R1, R1, R3

OR R2, R2, R7

ADD R3, R2, R1

STORE R3, 0(R8)

 

Number of cycles required to complete the given sequence of instructions in a 5 stage (IF, ID, EX, Mem, WB) RISC processor with operand forwarding_____

Answer 1

Total 10 cycles needed . 

There is EX- EX stage operand forwarding between instructions I2-I3, I4-I5, I3-I5

and I5-I6

Comments

i think it needs 11 cycles,because the last instruction need the value of r3 which is avaliable after the above instruction writes in mem.