In ______ addressing mode, the operands are stored in the memory. The address…
2016
In ______ addressing mode, the operands are stored in the memory. The address of the corresponding memory location is given in a register which is specified in the instruction.
Answer: B. Register indirect — Answer: Register indirect addressing. Definition: The instruction specifies a register whose contents are treated as the memory address of the operand. The…
- A.
Register direct
- B.
Register indirect
- C.
Base indexed
- D.
Displacement
Attempted by 656 students.
Show answer & explanation
Correct answer: B
Answer: Register indirect addressing.
Definition: The instruction specifies a register whose contents are treated as the memory address of the operand. The operand itself is stored in memory at that address.
Mechanism: The effective address (EA) = contents of the specified register; the CPU fetches the operand from memory[EA].
Example: LOAD R1, (R2) means load into R1 the value stored at the memory address contained in R2 (R1 <- M[R2]).
Why the other addressing modes are not correct:
Register direct: The operand itself is in a register named by the instruction, so no memory address is involved.
Base indexed: The effective address is computed by adding a base register and an index register (EA = base + index), not taken directly from a single register.
Displacement: The effective address is base register plus a constant offset (EA = base + displacement), again different from simply using the register contents as the full address.
A video solution is available for this question — log in and enroll to watch it.