8085A datapath components Within the Intel 8085A microprocessor, which named block performs arithmetic and logic functions such as addition, subtraction, AND, OR, XOR, increment, and compare?

Introduction / Context:
Microprocessor block diagrams separate control, datapath, and interface functions. The arithmetic logic unit (ALU) is the core datapath block that executes arithmetic and bitwise operations on register data.

Given Data / Assumptions:

• Target device: Intel 8085A, a classic 8-bit microprocessor.
• Operations include arithmetic (add, subtract) and logic (AND, OR, XOR, NOT).
• Control and status flags reflect ALU results (zero, sign, carry, parity, auxiliary carry).

Concept / Approach:
The ALU receives operands from internal registers (for example, accumulator and a general-purpose register), performs the selected operation, sets flags, and writes the result back to a destination register. The CPU (central processing unit) is the overall chip; ALU is a specific functional sub-block within it. I/O refers to external interface logic, not the executing arithmetic engine.

Step-by-Step Solution:

Verification / Alternative check:
8085A documentation lists ALU operations and related flags; instruction mnemonics (ADD, SUB, ANA, ORA, XRA, CMP) all target the ALU.

Why Other Options Are Wrong:

• CPU: The entire processor; too broad.
• I/O: Handles external data transfers; not arithmetic.
• None of the above: Incorrect because ALU is the established term.

Common Pitfalls:
Using “CPU” and “ALU” interchangeably. The CPU contains the ALU but also includes registers, control unit, buses, and timing circuits.

Final Answer:
ALU