MHRD is good. Learn a simplified HDL and, starting with NAND gates, build increasingly complex things such as multiplexors, memory, an ALU, until you eventually

MHRD is good. Learn a simplified HDL and, starting with NAND gates, build increasingly complex things such as multiplexors, memory, an ALU, until you eventually end up with an (extremely simple, but functional) processor. It's essentially the first part of nand2Tetris as a game, but you are constrained by having a very limited amount of screen space (N lines of M characters, don't remember exactly how many, but essentially one screen's worth on the 80's era hardware the game is emulating for your dev environment) to work with for each component (e.g. if you were building an 8kb memory module and tried to copy/paste the code that makes up a 2kb module 4x times you'd run out of lines or characters, but instantiating 4x2kb modules would only take a few lines).