ITPEC FE Morning October 2019 Question 12

Instruction Register — holds the fetched instruction before decoding.

The diagram shows the instruction fetch path:

Main memory → a → Instruction decoder

• •a = Instruction register — temporarily stores the instruction fetched from memory so the decoder can interpret it

Why not others:
- (a) Accumulator — stores arithmetic/logic results, not part of the fetch cycle
- (b) Data cache — caches data, not instructions in this context
- (d) Program counter — holds the address of the next instruction, not the instruction itself

Key rule: In the fetch-decode-execute cycle, the instruction register sits between memory and the decoder, holding the current instruction.

AI-generated — may contain errors