Since the invention of the personal computer, software developers have used x86 assembly language to create innovative solutions for a wide variety of algorithmic challenges. During the early days of the PC era, it was common practice to code large portions of a program or complete applications using x86 assembly language. Given the 21st Century prevalence of high-level languages such as C++, C#, Java, and Python, it may be surprising to learn that many software developers still employ assembly language to code performance-critical sections of their programs. And while compilers have improved remarkably over the years in terms of generating machine code that is both spatially and temporally efficient, situations still exist where it makes sense for a software developer to exploit the benefits of assembly language programming.

The single-instruction multiple-data (SIMD) architectures of modern x86 processors provide another explanation for the continued interest in assembly language programming. A SIMD-capable processor contains computational resources that facilitate simultaneous calculations using multiple data values, which can significantly improve the performance of applications that must deliver real-time responsiveness. SIMD architectures are also well-suited for computationally-intense problem domains, such as image processing, audio and video encoding, computer-aided design, computer graphics, and data mining. Unfortunately, many high-level languages and development tools are still unable to fully or even partially exploit the SIMD capabilities of a modern x86 processor. Assembly language, on the other hand, enables the software developer to take full advantage of a processor’s SIMD resources.