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IB DP Computer Science — A1 Computer fundamentals — Computer hardware and operation | SL | A1.1.5
📋 What You Will Learn
- Describe the basic operations a CPU performs to execute one machine-language instruction
- State what happens to each register (PC, MAR, MDR, IR, AC) in each stage of the cycle
- Describe how memory and registers interact via the address, data and control buses
- Trace a short machine-language program through complete fetch–decode–execute cycles
- Explain why the PC is incremented during fetch and how branching changes it
🔁 Why This Matters A CPU is like a worker at a conveyor belt following a numbered to-do list: read the next numbered card (fetch), work out what it means (decode), do it (execute) — then repeat, millions of times per second. Every program you have ever run, however complex, is executed as exactly this