Computer architecture – addressing modes In which addressing mode is the operand value given explicitly within the instruction itself?

Introduction / Context:
Addressing modes define how instructions reference data. Recognizing these modes is vital for assembly programming, compiler backend work, and understanding how CPUs execute code efficiently.

Given Data / Assumptions:

• The question asks for the mode where the operand value (a constant) is embedded in the instruction.
• Other modes provide addresses or perform address calculations rather than embedding the value.
• We consider conventional definitions used across many ISAs (e.g., x86, ARM, RISC-V).

Concept / Approach:

Immediate mode places the actual operand (a literal constant) directly in the instruction encoding. Absolute (or direct) mode places the memory address explicitly in the instruction. Indirect mode uses a pointer to find the address. Index mode adds an index register to a base to compute the address. Only immediate mode provides the value itself without a further memory fetch.

Step-by-Step Solution:

Verification / Alternative check:

Example: ADD R1, #5 uses an immediate literal 5. By contrast, ADD R1, [0x1000] (absolute) fetches from memory address 0x1000.

Why Other Options Are Wrong:

Absolute gives an address; indirect dereferences a pointer; index computes an address using base+offset. None embed the value itself like immediate mode does.

Common Pitfalls:

Confusing “explicit operand” (value) with “explicit address.” The question asks for the operand itself, not its location.

Final Answer:

immediate mode.