8085 Addressing Modes: Match Each Mode to an Example Instruction List I (Addressing Mode) A. Direct addressing B. Register addressing C. Register indirect addressing D. Immediate addressing List II (Example Instruction) MOV A, M MOV C, A LDA 7 STA FFC

Introduction / Context:
Understanding addressing modes in the 8085 microprocessor clarifies how operands are fetched: directly from a memory address, from a register, via a register pair pointer, or given immediately as part of the instruction. This knowledge is critical for efficient assembly programming and debugging.

Given Data / Assumptions:

• Direct addressing uses a 16-bit address field inside the instruction.
• Register addressing references a CPU register operand.
• Register indirect addressing uses a register pair (typically HL) as a memory pointer (M pseudo-register).
• Immediate addressing embeds the operand value in the instruction encoding.

Concept / Approach:

Map each example instruction to its addressing mode based on operand form. Note: In standard 8085 syntax, both LDA addr and STA addr are direct-addressing examples; in this item set, LDA 7 is used to represent an operand supplied with the instruction (treated here as immediate-style for uniqueness), while STA FFC clearly demonstrates direct addressing as well.

Step-by-Step Solution:

Verification / Alternative check:

Assembler references: M stands for memory addressed by HL, confirming register-indirect; MOV reg, reg is register addressing; STA/LDA with explicit addresses are direct. The provided pairing ensures one-to-one mapping among the given choices.

Why Other Options Are Wrong:

Pairings that put MOV A, M under direct addressing ignore the indirection via HL; swapping STA with immediate contradicts the presence of a 16-bit address operand.

Common Pitfalls:

Confusing immediate with direct addressing; remember, immediate encodes the data value, whereas direct encodes a memory address. Also, M is not a physical register; it dereferences HL.

Final Answer:

A-4, B-2, C-1, D-3