Q28

Consider a $4$ stage pipeline processor. The number of cycles needed by the four instructions $I1, I2, I3, I4$ in stages $S1, S2, S3, S4$ is shown below:

$$\begin{array}{|c|c|c|c|c|} \hline \textbf{} & \textbf {S1} &\textbf {S2} & \textbf {S3} & \textbf{S4 } \\\hline \textbf{I1}& 2 & 1 & 1 & 1 \\\hline \textbf{I2} & 1 & 3 & 2 & 2\\\hline \textbf{I3}& 2 & 1 & 1 & 3 \\\hline \textbf{I4} & 1 & 2 & 2 & 2 \\\hline \end{array}$$

What is the number of cycles needed to execute the following loop? For (i=1 to 2) {I1; I2; I3; I4;}