What are accumulators?

• A. Stores the results of memory fetch
• B. Holds the status flags
• C. Keeps instruction history
• D. Holds the results of calculations and logic operations that the ALU performs

Answer: (D)

An accumulator is a dedicated register in many CPU designs that holds the results produced by the arithmetic logic unit. After the ALU performs an arithmetic or logic operation, its result is written into the accumulator so that the most recent computation is readily available for the next operation or can be stored back to memory. This makes chaining calculations straightforward, since you keep the current result in one central place. It isn’t used for memory fetch results or for history of instructions, which are handled by other parts of the system, and status flags live in a separate flag register. So the accumulator’s role is to hold the results of calculations and logic operations that the ALU performs.