The _____ addressing mode is similar to register indirect addressing mode,…

Concept

Displacement addressing extends register-indirect addressing by adding a constant displacement from the instruction to the address held in a register.

If R is the specified register and A is the instruction's offset, the effective address is EA = (R) + A. With A = 0, it reduces to ordinary register-indirect addressing.

Application

1. The stem says that the instruction specifies both a register and an offset.

2. Adding that offset to the register contents gives EA = (R) + A, which is the defining form of displacement addressing.

3. The official UGC NET July 2016 Computer Science Paper III key identifies Displacement as the answer to this item.

Cross-check and contrast

The named modes can be separated by the terms used to form their effective addresses:

• Base-indexed addressing forms an effective address from a base-register value and an index-register value: effective address = base value + index value.

• This three-term addressing form combines a base-register value, an index-register value, and an instruction-supplied constant: effective address = base value + index value + constant.

• Indexed addressing uses an index-register term to locate an element relative to a supplied base or address; some architectures also scale that index term.

The stem supplies one register and one explicit instruction offset, so the required addressing mode is Displacement.