title: Is 8-byte alignment for "double" type necessary?
body: <p>I understand word-alignment, which makes the cpu only need to read once when reading an integer into a register. </p>
  
  <p>But is <a href="http://www.cs.umd.edu/class/sum2003/cmsc311/Notes/Data/aligned.html" rel="noreferrer">8-byte alignment</a> (let's assume 32bit system) for "double" necessary? What is the benefit? What will happen if the space for storing a "double" is just 4-byte alignment?</p>