GATE CS 1999 Q2.23 — Machine Instructions and Addressing Modes

To implement high-level programming language features, specific addressing modes are required. A processor supporting only immediate and direct addressing modes cannot support the following features:

• Pointers (A): Dereferencing a pointer requires accessing a memory location whose address is stored dynamically inside another variable or register. This requires indirect addressing, which is unavailable.
• Arrays (B): Accessing an element $A[i]$ where index $i$ is determined at runtime requires computing the address dynamically as $\text{Base} + i \times \text{size}$. This requires indexed or register-indirect addressing.
• Records (C): General records (especially when allocated dynamically or passed by reference) require base-register with displacement addressing to access fields at runtime.
• Recursive procedures with local variables (D): Recursion requires a dynamic stack. Local variables inside recursive calls are stored in activation records on the stack, requiring stack-pointer relative or base-register addressing to access them. Direct addressing cannot resolve these dynamic stack addresses.

Thus, none of these features can be implemented on the given processor, making all options correct.