HSLAM shares characteristics common to other assembler programs. For example, it translates any basic computer instruction into binary code - the final form of code that can be processed by a computer.

HSLAM had many enhancements over IBM's older assembler programs such as DOS/VSE and VSE/AF. For example, HLASM included support for older applications, common task automation and cross-referencing, allowing for more efficient development and administration. HLASM also improved debugging power, providing greater code-finding efficiency.