Instructions:
- Answer all questions. Write your answers in the spaces provided.
- The number of marks available is shown in brackets for each question.
- Suggested time: 30 minutes.
1 FDE Cycle[1 mark]
Name the three stages of the fetch-decode-execute cycle in the correct order.
2 FDE Cycle[3 marks]
Describe what happens during the fetch-decode-execute cycle. Give three distinct points.
3 Registers[4 marks]
Complete the table below. Write the name of the register or its purpose.
| Register | Purpose |
|---|
| Stores the address of the next instruction to be fetched from memory. Its value is incremented during each cycle. |
| Memory Data Register (MDR) | |
| Stores the address of the memory location currently being read from or written to. |
| Accumulator (ACC) | |
4 CPU Components[4 marks]
Describe the purpose of the Control Unit (CU) and the Arithmetic Logic Unit (ALU) within the CPU. Give two points for each.
(a) Control Unit (CU)[2 marks]
(b) Arithmetic Logic Unit (ALU)[2 marks]
5 Von Neumann / Stored Program[5 marks]
Tick (✓) one box in each row to show whether each statement is True or False.
| Statement | True | False |
|---|
| The ALU performs arithmetic calculations and logical comparisons. | | |
| The Program Counter stores the instruction currently being executed. | | |
| In Von Neumann architecture, programs and data share the same memory space. | | |
| The Memory Data Register stores the address of a memory location. | | |
| The Current Instruction Register holds the instruction currently being decoded. | | |
6 Stored Program Concept[2 marks]
Explain what is meant by the stored program concept.
7 Registers[3 marks]
A student claims: "The Program Counter stores a copy of the instruction currently being run by the CPU."
State whether this claim is correct or incorrect, and justify your answer.
8 CPU & RAM[2 marks]
Describe how the CPU and RAM work together when a program is running.