Describe how the accumulator is used during the Fetch-Decode-Execute cycle

The Fetch-Decode-Execute cycle, also known as the instruction cycle, is the basic operational process of a computer. The accumulator plays a crucial role in this cycle. Here's how it works:

1. Fetch: The cycle begins with the fetch operation. The Central Processing Unit (CPU) fetches the instruction from its memory. The Program Counter (PC) holds the memory address of the next instruction that needs to be fetched. This instruction is then placed into the Instruction Register (IR). The accumulator is not directly involved in this step.

2. Decode: In this step, the Control Unit (CU) decodes the instruction that has been fetched. It determines what operation needs to be performed. Again, the accumulator is not directly involved in this step.

3. Execute: This is where the accumulator comes into play. The decoded instruction is executed. If the operation is an arithmetic or logic operation, it is carried out by the Arithmetic Logic Unit (ALU). The result of this operation is stored in the accumulator. For example, if the operation is to add two numbers, the ALU performs the addition and the result is stored in the accumulator. The accumulator thus acts as a temporary storage area for the result of the operation.

4. Store: After the execution, the result stored in the accumulator may be transferred back to memory or to an output device.

So, in summary, the accumulator is used in the execute phase of the Fetch-Decode-Execute cycle to hold the result of an operation.