Systems ArchitectureExam Tips
Exam Tips - PC and Accumulator
Part of Program Counter & Accumulator — GCSE Computer Science
This exam tips covers Exam Tips - PC and Accumulator within Program Counter & Accumulator for GCSE Computer Science. Revise Program Counter & Accumulator in Systems Architecture for GCSE Computer Science with 15 exam-style questions and 12 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 7 of 7 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 7 of 7
Practice
15 questions
Recall
12 flashcards
Exam Tips - PC and Accumulator
Common exam questions and how to answer them:
- "When does the PC change?" → During the FETCH stage, it increments by 1
- "When does the ACC change?" → During the EXECUTE stage, when ALU stores a result
- "What does the PC hold?" → The address (not the instruction itself!) of the NEXT instruction
- "What does the ACC hold?" → The result of the most recent ALU operation
Common mistakes to avoid:
- Saying PC holds "the current instruction" - it holds the ADDRESS of the NEXT instruction
- Saying PC increments during EXECUTE - it increments during FETCH
- Confusing ACC with other registers (MAR/MDR) - ACC is specifically for ALU results
- Forgetting that branch/jump instructions change the PC to non-sequential addresses