Introduction

The machines we call “computers,” including modern desktop computers, laptops, and web servers, are remarkably fast and capacious. However, computer hardware is also embedded in devices that do not fit the traditional definition of computers: home appliances, automobiles, smart thermostats, tools, and televisions. Along with being energy-efficient and affordable, these devices may also need to be lightweight, portable, or even wearable. For these reasons, embedded systems have meager processing speed and memory capacity. This chapter focuses on low-level programming languages, which are used in practice to create software for resource-constrained devices. Efficiency is critical to making these devices useful and economically viable. The efficiency of embedded software is make-or-break; in other words, if we can write efficient code that runs fast and uses little memory, we enable technologies that can help people with their daily lives. Therefore, computer scientists place considerable emphasis on the efficiency and speed of low-level languages, which is why low-level languages are important to society. For efficiency reasons, the syntax of low-level programming languages relies on instructions that are computer-centric and challenging for humans to work with. This has led computer scientists to create “middle-level” languages that emphasize human-readability without compromising efficiency.

Consider our fictional company, TechWorks, which is bringing a line of next-generation prosthetics to the market. While legacy prosthetics are sometimes awkward to use and limited in function, “smart” prosthetics can be revolutionary. These prosthetics are computer-controlled, Internet-connected, and make use of artificial intelligence, allow those who need prosthetics to enjoy a quality of life that meets or exceeds expectations.

Computer control refers to the ability to manage, organize, or run something on a computer, whereas intelligent control is a class of control techniques that use various artificial intelligence computing approaches. For example, artificial intelligence algorithms can accurately determine the intentions of the wearer and control a prosthetic’s motion in an accurate and natural way. Internet connectivity means devices can be conveniently controlled by applications, relay telemetry to healthcare providers, and automatically apply over-the-air updates. TechWorks has fitted a small, inexpensive, energy-efficient system-on-chip computer to their devices, and are using the middle-level language C to implement these features efficiently.