What does indexed addressing modify in the address field for memory access?

What does indexed addressing modify in the address field for memory access?

• A. Addition of a constant value
• B. Multiplication of the address by two
• C. Substitution with a zero
• D. Reversal of the address order

Answer: (A)

Indexed addressing is a technique used in computer architectures to calculate effective addresses for memory access by adding a constant value (the index) to a base address. This method allows for efficient access to arrays or data structures where an element's location is determined by an offset from a base address. In indexed addressing, the base address points to the start of the array, while the index acts as an offset that varies depending on which element of the array is being accessed. By adding this constant value to the base address, the actual memory address for the desired data element can be quickly computed. This is particularly useful for iterating through arrays, as it streamlines the process of accessing each element by incrementing the index. Other methods of addressing do not affect the address field in the same manner as indexed addressing. For instance, multiplication, substitution with zeros, or reversing address order would not facilitate the straightforward access pattern needed for indexed addressing, which is fundamental in operations involving sequential data storage and retrieval. Thus, the addition of a constant value is the key aspect that defines how indexed addressing modifies the address field for memory access.

Indexed addressing is a technique used in computer architectures to calculate effective addresses for memory access by adding a constant value (the index) to a base address. This method allows for efficient access to arrays or data structures where an element's location is determined by an offset from a base address.

In indexed addressing, the base address points to the start of the array, while the index acts as an offset that varies depending on which element of the array is being accessed. By adding this constant value to the base address, the actual memory address for the desired data element can be quickly computed. This is particularly useful for iterating through arrays, as it streamlines the process of accessing each element by incrementing the index.

Other methods of addressing do not affect the address field in the same manner as indexed addressing. For instance, multiplication, substitution with zeros, or reversing address order would not facilitate the straightforward access pattern needed for indexed addressing, which is fundamental in operations involving sequential data storage and retrieval. Thus, the addition of a constant value is the key aspect that defines how indexed addressing modifies the address field for memory access.