Fetch Decode Execute Cycle

Question 1

Describe the fetch, decode, execute cycle

Answer 1

• cpu fetches instruction from memory addr
• control unit decodes op code
• cpu executes instruction
• cpu updates system & registers based on the instruction executed
• program counter points to next instruction

Question 2

What is cache memory and how does it contribute to performance?

Answer 2

Cache memory is the smallest of the memory hierarchy, living close to the CPU to provide access to frequently requires instructions or data. This is performant as it reduces the need to perform the whole fetch decode cycle from other memory locations.