<human>: Could you distill the essence of the text into 1-3 sentences?

So like the title says, I want to learn to build a CPU. I mean obviously I can't make like some intel i9 chip or anything, the ones made in other games have both only been 16-bit, heck I'd be willing to just make it 8-bit even, this is just something I want to do. So what books (preferably free ebooks?) would I have to read? Or websites or whatever. And what do I need to learn about? I know there's something called an ALU I need to learn about, but that's about all I know really.
<bot>: I want to learn to make a low powered processor in a game, like what has been done in LBP and Minecraft, what do I need to learn?