What Is an Assembly Language?

An assembly language is a type of low-level programming language that is intended to communicate directly with a computer’s hardware. Unlike machine language, which consists of binary and hexadecimal characters, assembly languages are designed to be readable by humans.

Low-level programming languages such as assembly language are a necessary bridge between the underlying hardware of a computer and the higher-level programming languages—such as Python or JavaScript—in which modern software programs are written.

Key Takeaways

  • An assembly language is a type of programming language that translates high-level languages into machine language.
  • It is a necessary bridge between software programs and their underlying hardware platforms.
  • Today, assemble languages are rarely written directly, although they are still used in some niche applications such as when performance requirements are particularly high.

How Assembly Languages Work

Fundamentally, the most basic instructions executed by a computer are binary codes, consisting of ones and zeros. Those codes are directly translated into the “on” and “off” states of the electricity moving through the computer’s physical circuits. In essence, these simple codes form the basis of “machine language”, the most fundamental variety of programming language.

Of course, no human would be able to construct modern software programs by explicitly programming ones and zeros. Instead, human programmers must rely on various layers of abstraction that can allow themselves to articulate their commands in a format that is more intuitive to humans. Specifically, modern programmers issue commands in so-called “high-level languages”, which utilize intuitive syntax such as whole English words and sentences, as well as logical operators such as “And”, “Or”, and  “Else” that are familiar to everyday usage.

Ultimately, however, these high-level commands need to be translated into machine language. Rather than doing so manually, programmers rely on assembly languages whose purpose is to automatically translate between these high-level and low-level languages. The first assembly languages were developed in the 1940s, and although modern programmers spend very little time dealing with assembly languages, they nevertheless remain essential to the overall functioning of a computer. 

Real World Example of an Assembly Language

Today, assembly languages remain the subject of study by computer science students, in order to help them understand how modern software relates to its underlying hardware platforms. In some cases, programmers must continue to write in assembly languages, such as when the demands are performance are especially high, or when the hardware in question is incompatible with any current high-level languages.

One such example that is relevant to finance are the high-frequency trading (HFT) platforms used by some financial firms. In this marketplace, the speed and accuracy of transactions is of paramount importance in order for the HFT trading strategies to prove profitable. Therefore, in order to gain an edge against their competitors, some HFT firms have written their trading software directly in assembly languages, thereby making it unnecessary to wait for the commands from a higher-level language to be translated into machine language.