Q47

Consider the following code sequence having five instructions from $I_1 \text{ to } I_5$. Each of these instructions has the following format. OP Ri, Rj, Rk Where operation OP is performed on contents of registers Rj and Rk and the result is stored in register Ri. $I_1$: ADD R1, R2, R3 $I_2$: MUL R7, R1, R3 $I_3$: SUB R4, R1, R5 $I_4$: ADD R3, R2, R4 $I_5$: MUL R7, R8, R9 Consider the following three statements. S1: There is an anti-dependence between instructions $I_2 \text{ and } I_5$ S2: There is an anti-dependence between instructions $I_2 \text{ and } I_4$ S3: Within an instruction pipeline an anti-dependence always creates one or more stalls Which one of the above statements is/are correct?