(i) Design suitable instruction formats for the machine. Specify the size of different fields that are needed in the instruction format. Also, indicate how many bits of the instructions are unused for this machine. Explain your design of the instruction format. Also, indicate the size of each register.

Instruction Format Design:

1. Operation Code (Op Code):

   - Size: 7 bits

   - Explanation: Represents one of the 128 operation codes.

2. Memory Operand:

   - Size: 16 bits

   - Explanation: Specifies the memory location for the instruction.

3. Register Operand:

   - Size: 16 bits

   - Explanation: Indicates the register involved in the operation.

4. Unused Bits:

   - Size: 7 bits (32 total bits - 7 bits Op Code - 16 bits Memory Operand - 16 bits Register Operand = 7 bits)

   - Explanation: These bits are unused and can be reserved for future expansions or other purposes.

Register Size:

   - General-Purpose Registers: 16 bits each

   - Accumulator Register: 16 bits

   - Program Counter (PC): 16 bits

   - Memory Address Register (MAR): 16 bits

   - Data Register (DR): 16 bits

   - Flag Registers (FR): Size not specified

Explanation:

   - The instruction format is designed to accommodate the machine's characteristics, considering a 32-bit fixed-length instruction.

   - The 7-bit operation code provides versatility with up to 128 different operations.

   - The 16-bit fields for memory and register operands ensure sufficient space for addressing and data.

   - The unused bits can be reserved for future enhancements or specific functionalities.

   - Register sizes are standardized at 16 bits for consistency in operand handling.

   - Special-purpose registers have sizes of 16 bits, assuming a similar word length.

This design balances the need for flexibility, addressing capabilities, and future scalability within the constraints of the machine's architecture.