FUNCTIONAL UNITS
REGISTER
INSTRUCTION EXECUTION
100

Programs and data stored 

Memory

100

Holds the instruction currently being executed

Instruction Register

100

First step 

Fetch 

200

Initiates control signals

Control Unit

200

Keep track of program execution

Program Counter

200

Second step

Decode

300

Perform arithmetic and logic operations  

ALU

300

Communicate with memory

MAR and MDR

300

Third Step

Execute

M
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