title: Good book to learn lower levels of computers
body: <p>I'm very interested in CPU and RAM, but way beyond the normal level of interest.</p>
  
  <p>I'd like to learn how memory and cpu's work especial on x86 and x64 processors. I'm due to embark on an assembly language course using NASM and want to get fully grounded before I start the course.</p>
  
  <p>A book that goes into detail about the registers and what they are used for, and how the CPU uses the memory. Topics on real mode and protected mode memory, and flat and segmented memory models would be a great help!</p>
  
  <p>Does anyone know of such books?</p>