Register allocation is a NP-hard problem. See "Register Allocation:What does the NP-completeness Proof of Chaitin et al. Really Prove?" via this thread on RTX2010 – Radiation-hardened stack machine microprocessor
What every programmer should know about memory, Part 1 [LWN.net] by Ulrich Drepper; September 2007. 9 part series.
Putting the "You" in CPU Curious exactly what happens when you run a program on your computer? Read this article to learn how multiprocessing works, what system calls really are, how computers manage memory with hardware interrupts, and how Linux loads executables.