An instruction format has the following structure: Instruction Number: Opcode destination reg, source reg-1, source reg-2 Consider the following sequence of instructions to be executed in a pipelined processor: I1: DIV R3, R1, R2I2: SUB R5, R3, R4I3: ADD R3, R5, R6I4: MUL R7, R3, R8 Which of the following statements is/are TRUE?

Let us analyze the read and write sets for each instruction based on the given format ($\text{Opcode } \text{dest}, \text{src1}, \text{src2}$):

• $\text{I1}$: Writes to $\text{R3}$, Reads from $\{\text{R1}, \text{R2}\}$

• $\text{I2}$: Writes to $\text{R5}$, Reads from $\{\text{R3}, \text{R4}\}$

• $\text{I3}$: Writes to $\text{R3}$, Reads from $\{\text{R5}, \text{R6}\}$

• $\text{I4}$: Writes to $\text{R7}$, Reads from $\{\text{R3}, \text{R8}\}$

Now, evaluating each given option:

• (A) $\text{I1}$ writes to $\text{R3}$ and $\text{I2}$ reads from $\text{R3}$. Since $\text{I1}$ precedes $\text{I2}$, this is a Read-After-Write (RAW) data dependency on $\text{R3}$. Thus, statement (A) is TRUE.

• (B) $\text{I1}$ writes to $\text{R3}$ and $\text{I3}$ writes to $\text{R3}$. This is a Write-After-Write (WAW) dependency, not a WAR dependency. Thus, statement (B) is FALSE.

• (C) $\text{I2}$ reads from $\text{R3}$ and $\text{I3}$ writes to $\text{R3}$. Since the read occurs before the write, this is a Write-After-Read (WAR) dependency, not RAW. Thus, statement (C) is FALSE.

• (D) $\text{I3}$ writes to $\text{R3}$ and $\text{I4}$ reads from $\text{R3}$. This is a Read-After-Write (RAW) dependency, not WAW. Thus, statement (D) is FALSE.

Hence, only statement (A) is correct.