Question 7907 – Addressing-Modes

Consider the C struct defined below:

    struct data   {
        int marks [100];
        char grade;
        int cnumber;
    };
    struct data student;

The base address of student is available in register R1. The field student.grade can be accessed efficiently using

Correct Answer: D

Question 10 Explanation:

sruct data
{
int marks[100];
char grade;
int cnumber;
}; struct data student
Base Address of student is available in R1.
So student.grade can be accessed efficiently by Relative Indexed Addressing Mode.
It is clearly mentioned X is the offset address to be summed with Base Address of R1.

Hence Index Addressing mode X(R1), where X is an offset represented in 2’s complement 16-bit representation.
⇾ Relative, Base Indexed & all subtypes of Indirect addressing modes are used with Arrays.

Post-increment addressing mode, (R1)+

Pre-decrement addressing mode, -(R1)

Index addressing mode, X(R1), where X is an offset represented in 2’s complement 16-bit representation