On Coursera, if I remember right, the first course gets you to the point where you have a CPU that can run machine language and an assembler. They give you an a

On Coursera, if I remember right, the first course gets you to the point where you have a CPU that can run machine language and an assembler. They give you an assembly version of Tetris that will run on what you built. In the second course you build the programming language that could be used to write Tetris, though I don't think you actually go through it as an exercise.