Addressing modes in computer architecture In which addressing mode is the memory address of the operand given explicitly within the instruction itself?
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AAbsolute mode
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BImmediate mode
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CIndex mode
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DModulus mode
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ENone of the above
Answer
Correct Answer: Absolute mode
Explanation
Introduction / Context:Addressing modes define how instructions reference their operands. Recognizing the differences helps with assembly programming, compiler design, and understanding generated machine code.
Given Data / Assumptions:
- We compare absolute (direct) addressing against immediate and indexed addressing.
- “Explicitly given address” means the instruction contains the target memory address as an operand field.
- Terminology: absolute mode is also called direct mode in many texts.
Concept / Approach:
Absolute addressing places the effective memory address directly in the instruction. Immediate mode embeds the data value, not an address. Index mode combines a base (often from a register) with an offset to compute the effective address at run time.
Step-by-Step Solution:
Interpret the phrase “address of the location of the operand is given explicitly”.Match that phrase to absolute (direct) addressing where EA = address field.Eliminate immediate mode (EA not used; operand is a literal) and index mode (EA computed as base + index).Select Absolute mode.Verification / Alternative check:
Assembly examples often show instructions like “LOAD A, 1000h” using direct addressing where 1000h is the memory address; this is absolute mode.
Why Other Options Are Wrong:
b: Immediate places the operand value in the instruction, not its address. c: Index computes an address from components at run time, not a single explicit address. d: “Modulus mode” is not a standard addressing mode.
Common Pitfalls:
Confusing “immediate value” with “address given immediately”; the former is data, not a pointer.
Final Answer:
Absolute mode