title: Is it more efficient to touch fewer registers in ARM assembly?
body: <p>I've just started learning Assembly via Raspbian and have a quick question: how efficient is saving register space in Assembly? For example, if I wanted to do a quick addition, is there a meaningful difference in </p>
  
  <pre><code>mov r1, #5
  mov r2, #3
  add r1, r1, r2
  </code></pre>
  
  <p>and </p>
  
  <pre><code>mov r1, #5
  mov r2, #3
  add r3, r1, r2     @ destination in a new register that wasn't previously used
  </code></pre>
  
  <p>(except storing in different registers)?</p>