Addressing Modes — Practice MCQs for CCAT

Correct Answer: B — Operand is in instruction itself

Immediate: operand value is directly in the instruction.

Correct Answer: B — Data in a register

Register addressing: operand is in a CPU register.

Correct Answer: A — Address in instruction points to memory

Direct: instruction contains memory address of operand.

Correct Answer: B — Instruction has address of address

Indirect: address in instruction points to another address.

Correct Answer: A — Uses index register + base

Indexed: effective address = base + index register.

Correct Answer: B — Relocatable code

Base addressing helps make code position-independent.

Correct Answer: B — Operand on top of stack

Stack addressing: operand implicitly on top of stack.

Correct Answer: C — Register

Register mode is fastest - no memory access needed.

Correct Answer: B — PC + offset

Relative: address = Program Counter + displacement.

Correct Answer: B — Increments register after use

Auto-increment: register value used then incremented.

Correct Answer: C — In the instruction itself

In immediate addressing, the operand value is part of the instruction itself, not in a register or memory.

Correct Answer: B — Register contains the memory address of operand

In register indirect addressing, a register contains the memory address where the operand is located.

Correct Answer: C — Base address + index register value

In indexed addressing, effective address = base address + contents of index register.

Correct Answer: B — Effective address = base register + displacement in instruction

In base-register addressing, effective address = contents of base register + displacement value in instruction.

Correct Answer: B — Branch and jump instructions

Relative addressing uses PC + offset to calculate address, commonly used for branch instructions to create position-independent code.

Correct Answer: B — No memory reference needed, fastest for constants

Immediate addressing requires no memory access to fetch operand as it is part of instruction, making it very fast for constants.

Correct Answer: C — Indexed

Indexed addressing is ideal for arrays as base address points to array start and index register holds element offset.

Correct Answer: A — Register is decremented before accessing operand

In auto-decrement mode, the register is decremented before it is used to access the operand.

Correct Answer: C — Relative (PC-relative) addressing

Relative addressing uses offset from PC, so code can be loaded anywhere in memory and still work correctly.

Correct Answer: B — The actual memory address computed by the addressing mode

Effective address is the final memory address calculated after applying the addressing mode calculations.

Correct Answer: B — Operand is implied by opcode, no address needed

In implied addressing, the operand is implicit in the instruction itself (e.g., CLA - clear accumulator).

Correct Answer: B — Limited address space determined by instruction size

Direct addressing is limited by the number of bits available for the address field in the instruction format.

Correct Answer: B — Uses base or PC plus displacement to calculate address

Displacement addressing combines a register (base or PC) with a displacement value to compute effective address.

Correct Answer: B — Multiple levels of pointers are followed

Multilevel indirect addressing follows multiple pointer references to reach the final operand.

Correct Answer: B — Scale factor (size of data element)

Scaled index addressing multiplies the index by the size of each element (1, 2, 4, or 8 bytes) for efficient array access.