title: Interrupting an assembly instruction while it is operating
body: <p>When an interrupt comes to CPU, it is handled by saving current address location prior jumping into the handler if it is acknowledged. Otherwise it is ignored.</p>
  
  <p>I wonder whether an assembly instruction call is interrupted.</p>
  
  <p>For example,</p>
  
  <pre><code>mvi a, 03h ; put 3 value into acc. in 8080 assembly
  </code></pre>
  
  <p>Can be the one line instruction interrupted? Or if not, it is atomic??</p>
  
  <p>Is there always a guarantee that "one line assembly instruction" is always atomic??</p>
  
  <p>What if there is no "lock" keyword i.e. in 8080 assembly, then how is the atomicity provided?</p>
  
  <p>For example, what if 64 bit sum is wanted to be operated, but there is no way to do it with "one line instruction" and an interrupt comes while operating on sum. How can it be prevented at assembly level??</p>
  
  <p>The concept is being started to boil down for me.</p>