The lower you get the more your model of computation must understand the host system; but be careful, even C statements often compile into surprisingly unexpect

The lower you get the more your model of computation must understand the host system; but be careful, even C statements often compile into surprisingly unexpected machine code. If you want to explore this route I recommend picking up an embedded hobby project; Ie grab an Odroid Go and write some fun little arduino games in C++ using the Esp-Idf toolkit. It's got two cores, some IO, and a slowish LCD; and so you'll have to understand async programming and have a mental model of the device's memory to get any satisfaction. But that still doesn't require much beyond most 200 level computing knowledge. :)