Describe the role of the MAR in the fetch–decode–execute cycle.

The Memory Address Register (MAR) plays a crucial role in the fetch-decode-execute cycle, which is the basic operational process of a computer.

1. Fetch: The first step in this cycle is fetching the instruction from the computer's memory. The address of the instruction to be fetched is held in the Program Counter (PC). The PC sends this address to the Memory Address Register (MAR). The MAR then accesses the memory location of the instruction and sends it to the Memory Data Register (MDR).

2. Decode: The next step is decoding the instruction. This is not directly related to the MAR, but it's worth mentioning that the instruction held in the MDR is sent to the Control Unit (CU) where it is decoded.

3. Execute: The final step is executing the instruction. Again, this step doesn't directly involve the MAR. The decoded instruction is executed, and the results are stored in the Accumulator.

In summary, the MAR's role in the fetch-decode-execute cycle is to hold the memory address of the instruction that needs to be fetched. It receives this address from the PC and then accesses the memory location of the instruction, sending it to the MDR.