Instruction Cycle

The time period during which one instruction is fetched from memory and executed when a computer is given an instruction in machine language. There are typically four stages of an instruction cycle that the CPUcarries out:
Fetch the instruction from memory. This step brings the instruction into the instruction register, a circuit that holds the instruction so that it can be decoded and executed.
Decode the instruction.
Read the effective address from memory if the instruction has an indirect address.
Execute the instruction.
Steps 1 and 2 are called the fetch cycle and are the same for each instruction. Steps 3 and 4 are called the execute cycleand will change with each instruction.

What are the steps involved in an instruction cycle.

Any program residing in the memory contains a set of instruction that need to be executed by the computer in a sequential manner. This cycle for every instruction is known as the instruction cycle . The cycle consists of the following steps:

- Fetch instruction: Like the name stated in this process the cpu fetches the instruction from the memory. The PC get loaded with the address of the instruction.

- Decode: the instruction: In this process the instruction gets decoded by the processor.

- In case the instruction has an indirect address the effective address is read from the memory.

- Fetch the operand from the memory

- Execution: once the instruction gets decoded the processor executes the instruction.

- Result: Store the result in the appropriate place.