title: What does dw, db and ? (question mark) mean in TASM struc?
body: <p>I'm new to assembly, and now I'm trying to figure out what do the <code>dw</code>, <code>db</code>, and <code>?</code> mean in a <code>struc</code>.</p>
  
  <p>For example here:</p>
  
  <pre><code>struc segment_descriptor
    seg_length0_15        dw      ?
    base_addr0_15         dw      ?
    base_addr16_23        db      ?
    flags                 db      ?
    access                db      ?
    base_addr24_31        db      ?
  ends segment_descriptor
  </code></pre>