what is Machine Cycle
February 21, 2019
Machine
Cycle
CPU performs following steps
to execute an instruction:
- Fetch
- instruction
- Execute Instruction
- Storing
1. Fetch
Instruction fetch is a
process of getting an instruction from the memory to execute it.
This process is performed by
the control unit.
2. Decode
instruction
The control unit decodes the
Instruction. This process examines the nature of
instruction to determine
what further operations should be taken. CU directs to move the
required data from memory to
ALU.
3.
Execute Instruction
After decoding the Instruction
and getting the required data, CPU finally executes that
Instruction. The instruction
is executed by ALU.
4.
Storing
The process of writing the
result to the memory IS called storing
These four operations
collectively are called a machine cycle or instruction cycle The
time required to fetch and
decode instruction is called Instruction time or i-time The time
required to execute and
store is called Execution time or e-time