Of course, as the author implies there's an MMU, register renaming, not to mention a whole OS involved, so how "exactly" are we talking about? As Blake wrote, there's "a world in a grain of sand".
(Of course I'm excited for you and share your pleasure in understanding memory layout and its implications. Computing is really fun the less abstract it is. And that sheer depth means we can plumb those depths -- or heights -- as far as we like).