The instruction cycle is 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 CPU carries out: An instruction is a form of communicated information that is both command and explanation for how an action, behavior, method, or task is to be begun, completed, conducted, or executed. ... Jump to: navigation, search This article needs to be cleaned up to conform to a higher standard of quality. ... Jump to: navigation, search A computer is a device or machine for processing information from data according to a program — a compiled list of instructions. ... A system of codes directly understandable by a computers CPU is termed this CPUs native or machine language. ...

• "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.

• "Store" in memory any results generated by the operation, or send the results to an output device.

Steps 1 and 2 are called the fetch cycle and are the same for each instruction. Steps 3 and 4 are called the execute cycle and will change with each instruction. In computing, an instruction register is the part of a CPUs control unit that stores an instruction. ...

The term refers to both the series of four steps and also the amount of time that it takes to carry out the four steps.

An instruction cycle also is called a machine cycle and fetch-and-execute cycle.