INSTRUCTION EXECUTION CYCLE

THE INSTRUCTION EXECUTION CYCLE.

The instruction execution cycle is included with the following steps;

1.FETCHES

2.DECODE

3.EXECUTE

4.STORE

HOW THE CPU EXECUTES PROGRAM INSTRUCTION ?

 Before an instruction can be executed,program instructions and data must be placed into memory from an input device or a secondary storage device.

1.  The control unit "FETCHES" (gets) the instruction from the memory.
2. The control unit "DECODES" (decides what it means) the instruction and gives instruction for necessary  data to be moved from memory to the arithmetic/logic unit.
3. The arithmetic/logic unit "EXECUTES" arithmetic and logic instruction.That is, the ALU is given control and performs the actual operation on the data.
4. The result of these operation is "STORED" in memory or in a temporary location called a register.