Verilog

Verilog is a language in which you write down how a computer chip should be structured inside. You type it into a computer like a regular program, and the text looks similar too. The difference: a normal program tells a finished chip what to do. Verilog, by contrast, describes the chip itself, meaning which components exist and how they are wired together. Experts call this kind of thing a hardware description language. From such a description, a real piece of silicon is eventually made, one that can no longer be changed afterward.

Why nobody draws chips by hand anymore

In the 1970s, engineers still drew a chip’s wiring traces individually on large plans. Back then, a processor had a few thousand transistors, meaning tiny electrical switches. Today there are many billions. Doing that by hand would be impossible, even with a huge team working over many years.

Verilog solves this problem by introducing a layer of abstraction. The engineer writes down what a circuit should accomplish, for example adding two numbers. A program called a synthesis tool then automatically translates this into the concrete wiring. It’s similar to how an architect draws a floor plan without sketching every single brick.

This is directly relevant to the AI industry. Specialized chips for AI computations, such as Nvidia's graphics cards or Google's in-house computing chips, are all created this way. Whoever gets from design to finished chip faster has a tangible advantage in the market.

From text to silicon

A Verilog description consists of modules. A module is a self-contained building block with inputs and outputs, such as a counter or a memory element. Modules can contain other modules, much like an engine is made up of cylinders and valves. A large chip is, in the end, a tree made up of thousands of such building blocks.

One important difference from regular programming languages: in Verilog, the instructions don’t execute one after another. Everything happens simultaneously, because in a circuit all the wires are also carrying current at the same time. This is exactly where beginners who previously learned Python or Java often struggle. They write code that in their mind runs step by step, but that behaves completely differently in hardware.

Before a design goes into production, it is extensively simulated. A simulator runs through the circuit on a computer and checks whether it responds correctly to all possible inputs. This is crucial, because a bug in the finished chip can no longer be fixed with an update. A single production run often costs several million euros, which is why teams test for months before releasing the design.

Verilog in companies, academia, and AI headlines

Practically every chip in your everyday life came about this way: the processor in your phone, the chip in your bank card, the control electronics in your car. Verilog and its European rival language VHDL largely split this market between them. In the US and Asia, Verilog dominates, often in its extended form SystemVerilog.

Anyone studying electrical engineering or computer engineering usually encounters Verilog in the second or third semester. For practice, an FPGA is often used. This is a chip whose wiring can be reprogrammed afterward. This allows you to try out your own design without having to commission an expensive chip factory.

In tech news, Verilog currently comes up mainly in connection with AI. Several research groups and companies are testing whether language models can write usable Verilog code. The results so far are mixed: it works decently for small building blocks, but not yet for complete processors. Should it improve, this could significantly speed up the development of new chips.