In most general case, the computer needs to process each instruction with the…
2023
In most general case, the computer needs to process each instruction with the following sequence of steps :
(A) Calculate the effective address
(B) Execute the instruciton
(C) Fetch the instruction from memory
(D) Fetch the operand from memory
(E) Decode the instruction
Choose the correct answer from the options given below :
- A.
(A), (B), (C), (D), (E)
- B.
(A), (B), (C), (E), (D)
- C.
(C), (E), (A), (D), (B)
- D.
(C), (E), (D), (A), (B)
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Correct answer: C
Correct sequence:
Fetch the instruction from memory.
Decode the instruction.
Calculate the effective address for any memory operands (if required).
Fetch the operand(s) from memory (if the instruction needs them).
Execute the instruction.
Reason:
The processor must fetch the instruction from memory before it can be decoded or acted upon.
Decoding identifies the operation and addressing mode; addressing information is needed to compute any effective addresses.
Effective address calculation must occur before fetching memory operands, because the address tells the processor where to read the operand from.
Execution is the final step after all required data and addresses are available.
Note: In some implementations, parts of effective address calculation may overlap with decoding, but logically the order remains fetch → decode → effective address calculation → fetch operands → execute.
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