Electronics Engineering (ELEX) Board Practice Exam 2025 - Free ELEX Exam Practice Questions and Study Guide

The directive that indicates the start of memory allocation from a certain address in assembly language is ORG. This directive serves to define the origin of the memory location where the subsequent data or code will be allocated. When you use ORG, you specify an address, and from that point onward, the assembler will place the subsequent instructions or data in memory starting at that designated address.

For instance, if you write ORG 1000h, it tells the assembler to start assembling the following code or data at the memory address 1000 hexadecimal. This is crucial for organizing program segments and ensuring that they occupy the correct locations in memory, especially when working with low-level assembly programming or interfacing with hardware where specific addresses may be tied to particular functionalities.

Other directives like SEG, DATA, and CODE serve different purposes. SEG typically defines a segment of code or data, while DATA and CODE directives specify declarations or definitions of data and instruction segments respectively. However, they do not control memory allocation starting from a specific address the way ORG does.