<Dd> Performs floating - point operations . </Dd> <P> Each computer's CPU can have different cycles based on different instruction sets, but will be similar to the following cycle: </P> <Ol> <Li> Fetch the instruction: The next instruction is fetched from the memory address that is currently stored in the program counter and stored into the instruction register . At the end of the fetch operation, the PC points to the next instruction that will be read at the next cycle . </Li> <Li> Decode the instruction: During this cycle the encoded instruction present in the instruction register is interpreted by the decoder . </Li> <Li> Read the effective address: In the case of a memory instruction (direct or indirect) the execution phase will be during the next clock pulse . If the instruction has an indirect address, the effective address is read from main memory, and any required data is fetched from main memory to be processed and then placed into data registers (clock pulse: T). If the instruction is direct, nothing is done during this clock pulse . If this is an I / O instruction or a register instruction, the operation is performed during the clock pulse . </Li> <Li> Execute the instruction: The control unit of the CPU passes the decoded information as a sequence of control signals to the relevant function units of the CPU to perform the actions required by the instruction such as reading values from registers, passing them to the ALU to perform mathematical or logic functions on them, and writing the result back to a register . If the ALU is involved, it sends a condition signal back to the CU . The result generated by the operation is stored in the main memory or sent to an output device . Based on the feedback from the ALU, the PC may be updated to a different address from which the next instruction will be fetched . </Li> </Ol> <Li> Fetch the instruction: The next instruction is fetched from the memory address that is currently stored in the program counter and stored into the instruction register . At the end of the fetch operation, the PC points to the next instruction that will be read at the next cycle . </Li>

What are the steps to execute an instruction