What best describes the role of a special-purpose register in indexed addressing?

What best describes the role of a special-purpose register in indexed addressing?

• A. To perform calculations
• B. To hold the operation codes
• C. To store the index value for address modification
• D. To manage signal integrity

Answer: (C)

In indexed addressing, a special-purpose register is crucial for determining the effective address of an operand. The role of this register is to store the index value, which is then added to a base address to calculate the memory location of the data being accessed. This allows for efficient access to arrays and data structures where the information resides in contiguous memory locations. Using indexed addressing enhances the flexibility of addressing modes, enabling programs to handle data more dynamically. By using a special-purpose register to hold the index value, the system can quickly modify addresses without needing to re-specify the entire address value, significantly speeding up access times for frequently used data. Other choices, while relevant to computing, do not describe the specific function of a special-purpose register in indexed addressing. For example, performing calculations typically refers to the Arithmetic Logic Unit's function, operation codes pertain to the instructions being executed rather than addressing mechanisms, and managing signal integrity relates to the physical aspects of signal transmission rather than data addressing.

In indexed addressing, a special-purpose register is crucial for determining the effective address of an operand. The role of this register is to store the index value, which is then added to a base address to calculate the memory location of the data being accessed. This allows for efficient access to arrays and data structures where the information resides in contiguous memory locations.

Using indexed addressing enhances the flexibility of addressing modes, enabling programs to handle data more dynamically. By using a special-purpose register to hold the index value, the system can quickly modify addresses without needing to re-specify the entire address value, significantly speeding up access times for frequently used data.

Other choices, while relevant to computing, do not describe the specific function of a special-purpose register in indexed addressing. For example, performing calculations typically refers to the Arithmetic Logic Unit's function, operation codes pertain to the instructions being executed rather than addressing mechanisms, and managing signal integrity relates to the physical aspects of signal transmission rather than data addressing.