GATE CS 2002 Q1.24 — Machine Instructions and Addressing Modes

In computer architecture, addressing modes define how the CPU determines the effective address of an operand. Let us analyze each option to identify the correct definition of absolute addressing mode:

• Option A: "the operand is inside the instruction" describes Immediate Addressing Mode (e.g., ADD #5).
• Option B: "the address of the operand is inside the instruction" describes Absolute (or Direct) Addressing Mode. Here, the instruction directly contains the memory address of the operand (e.g., LDA 2000H).
• Option C: "the register containing the address of the operand is specified inside the instruction" describes Register Indirect Addressing Mode (e.g., MOV A, [R1]).
• Option D: "the location of the operand is implicit" describes Implied (or Implicit) Addressing Mode (e.g., CMA which complements the accumulator).

Thus, in absolute addressing mode, the address of the operand is directly specified inside the instruction.