title: what exactly is program stack's growth direction?
body: <p>I'm reading <em>Professional Assembly Language</em> by Richard Blum,and I am confusing about a Inconsistency in the book and I wondering what exactly is  program stack's growth direction?
  This is the picture from page 312, which is suggesting that program stack grows up.</p>
  
  <p><img src="https://i.stack.imgur.com/FxBEm.png" alt="enter image description here"></p>
  
  <p>But when I reached page 322，I see another version, which suggesting that program stack grows down.
  <img src="https://i.stack.imgur.com/8efYZ.png" alt="enter image description here"> </p>
  
  <p>and this </p>
  
  <p><img src="https://i.stack.imgur.com/LccTN.png" alt="enter image description here"></p>