I have been studying how processors work and its different parts including the ALU, registers, control unit, and a question came to my mind concerning multi-core processors. What are the cores made of? Is it another complete processor, or is it just one of its parts? If it is another complete processor with its own parts, do all cores share the registers or they are the same registers for all cores? And does every core need to have its own data and address lines? If not, what is the part shared among the cores?
Processors are and have been made of such components as the Algorithmic Unit and the Control Unit etc etc since they began, in fact I have a book explaining the architecture of the CPU that came before the Commodore 64.
Each core in itself is like a single core CPU, it even has it's own Cache called L1 Cache. Outside of the cores is the L2 Cache and L3 Cache, they're tiered in such a way that some of the cache is "proprietary" to a core and higher up is shared. That's also why the higher levels have more cache.
But before you're bored to death with structure, what is a processor made of? Super duper pure silicon (1 ppb foreign contaminant), a molecule derived from refining sand. How it's made can be found in a 2011 Intel Presskit: From Sand to Silicon – the Making of a Chip There's also a few good YouTube videos if you google it.
Yes every core needs it's own address lines. Neat thing about cores, a great way to understand them is if you get a motherboard that supports multiple processors. I happen to have experience with many Server Blades including the one behind me in the closet, which supports multiple processors. Neat thing about it, just like the shared and private cache, each processor requires in own memory (DDR#). But when you boot up your machine you'll generally only be told you've doubled your CPUs (cores).
I'd go on about die maps and how memory I/O and graphics processing works on modern processors but I think it's said a lot better than I'll ever be able to explain on Wikipedia. Here's the whole wiki on processors: Wikipedia: Processors