Machine language and processor dependence: Is machine language independent of the type of microprocessor used in a computer system?

Introduction / Context:
Machine language is the lowest-level software representation of instructions a specific CPU can execute. Different microprocessors implement different instruction sets, encodings, and execution semantics. This question probes whether you correctly identify machine code as CPU-specific rather than universal.

Given Data / Assumptions:

• Each CPU family (e.g., 8085, 8051, AVR, ARM) defines its own instruction set and opcode encodings.
• Binary images are interpreted according to the target CPU’s ISA.
• No compatibility layer (such as a software emulator) is assumed.

Concept / Approach:
Because opcodes are simply patterns of bits, they only gain meaning relative to a CPU’s decoder. An opcode that means “ADD” on one architecture could be invalid or mean something else on another. Therefore, machine language is inherently processor dependent. Portability requires recompilation/assembly for the target ISA or an emulator that translates foreign opcodes.

Step-by-Step Solution:

Verification / Alternative check:
Try to execute an 8085 binary on an 8051: the CPU will not interpret the opcodes correctly. Cross-assemblers generate different binaries for different targets from the same source, confirming dependence on ISA.

Why Other Options Are Wrong:

• “Independent” claims contradict the definition of ISA.
• “Independent only for arithmetic” is incorrect; all encodings are ISA-specific.
• “Independent if you use an emulator” shifts execution to the emulator; the underlying dependency remains.
• “Independent for 8-bit only” is false; bit width does not change ISA dependence.

Common Pitfalls:
Assuming source code portability implies binary portability; ignoring endianness, calling conventions, and instruction encodings when moving binaries between architectures.

Final Answer:
Dependent: machine code is specific to the microprocessor ISA