Often the documentation you need is hard to find. Intel needs to extend some effort in cataloging their documentation (and making the catalog easy to find).
Lacking that, use Google, enter in the search phrase
Architectures Optimization site:intel.com
The top item in my search is a .PDF document titled:
Intel 64 and IA-32 Architectures Optimization Reference Manual
Order Number: 248966-023
Chapter 2.2.4 should get you started.
Once you get familiar with how to locate the correct document (where to find, how to search), then you will be able to find the answers to your questions.