This is not for everyone, but if you work a lot with computers at a lower level, you will probably enjoy the idea of building your own CPU sooner or later. There was a time when it was a huge undertaking, but with today’s tools and FPGA it’s… well, not easy, but certainly easy. If you have the urge to try it yourself, you can see it [Simply Explained’s] Video series called “Building Scots CPU”.
The 11 videos cover everything from basic transistor logic to sequential circuits and move on to things like ALUs, clock units and how jump instructions work.
We’re guessing some more videos are coming. However, these 11 videos have more than two hours of content and that’s a lot to get you started. Of course, everyone who does this usually focuses on one type of architecture as needed but there are many ways you can design a CPU. Many homebrew design guidelines are simple multiple watches per design. Uses the pipeline to get an instruction every hour once the pipeline is full. Modern CPUs do a lot of tricks to actually implement multiple instructions per clock cycle, but it complicates a lot.
Then there are non-traditional architectures such as single-direction computers or asynchronous CPUs. The point is, once you know how a basic CPU works, there’s still plenty of room for innovation in your own design.
We’ve done this exercise more than once and – in our opinion – the hardest part is not building the CPU. It makes all the accessories you need to do everything you need to do. There are some hacks to make it easier. On the other hand, everything from A to Z is possible.