1
Q
Fetch - MAR <- PC
A
PC (address of next instruction) copied to MAR.
2
Q
Fetch - PC <- Memory
A
Instruction held at MAR copied to MBR.
Contents of PC incremented by 1 to prepare for next instruction.
3
Q
Fetch - CIR <- MBR
A
Contents of MBR copied to CIR.
Frees up space in MBR for executing.
4
Q
Decode - CIR
A
Instruction in CIR decoded.
5
Q
Execute - CIR
A
Instruction in CIR executed.
Result stored in accumulator.
