title: What do ds:si and es:di mean in assembly?
body: <blockquote>
    <p>The movsb (move string, bytes) instruction fetches the byte at address
    ds:si, stores it at address es:di, and then increments or decrements
    the si and di registers by one.</p>
  </blockquote>
  
  <p>I know esi,si and edi,di registers, </p>
  
  <p>but not <code>ds:si</code> and <code>es:di</code> ,</p>
  
  <p>what do they mean?</p>