Mnemonic codes and machine codes are two different representations of instructions used in computer programming and assembly language programming. They serve distinct purposes and have specific characteristics:

1. Machine Code:

•   Binary Representation: Machine code consists of binary numbers that the computer's central processing unit (CPU) directly understands and executes. Each instruction is represented by a sequence of 0s and 1s.
•   Low-Level: Machine code is the lowest level of programming language. It is specific to the computer's architecture and is not human-readable or easily understandable.
•  Hardware Dependent: Machine code is machine-dependent, meaning it varies from one type of CPU architecture to another. Programs written in machine code are not portable and must be tailored to a specific hardware platform.
• Efficiency: Machine code is highly efficient because it directly corresponds to the CPU's native instructions. It allows for fine-grained control over hardware resources.

2. Mnemonic Code:

•   Symbolic Representation: Mnemonic code is a higher-level representation of machine code instructions. It uses human-readable symbols, or mnemonics, to represent instructions and operands. For example, "MOV" might represent a move instruction, and "R0" could represent a register.
•   Human-Readable: Mnemonic code is designed to be human-readable and easier for programmers to understand and work with. It simplifies the coding process by providing a more intuitive way to write instructions.
•   Hardware-Independent: Mnemonic code is usually not tied to a specific hardware architecture. Instead, it's associated with a particular assembly language that can be used across different machines with the same architecture.
•  Portability: Programs written in mnemonic code are more portable than machine code because they can be translated into machine code for different hardware platforms with the appropriate assembler or compiler.

In summary, the key difference between mnemonic codes and machine codes lies in their representation and abstraction level. Machine code is the raw binary language that CPUs understand directly, while mnemonic code is a higher-level, human-readable representation of those instructions. Mnemonic code simplifies programming and enhances portability, making it easier for programmers to write and maintain code for specific architectures without having to delve into the intricacies of machine code.