title: When Will the Code Under DATA SEGMENT execute in this code?
body: <p>I am a beginner of Assembly Programming...
  I surfed a lot in google. There is a lot of information, but I still do not understand the following code. I would be grateful if someone could explain</p>
  
  <p>MOV AX,DATA</p>
  
  <p>I also don't understand when the code that is present in data segment would be executed in this program.</p>
  
  <pre><code>ASSUME CS:CODE,DS:DATA
  
  CODE SEGMENT
   MOV AX,@DATA
   mov DS,AX
   ...
   ...
  CODE ENDS
  
  
  DATA SEGMENT
     ...
     ...
     ... //SOMECODE
  DATA ENDS 
  </code></pre>
  
  <p>Also, can someone explain to me what the following instructions do?..</p>
  
  <p><code>MOV AH , ??H ( ?? can be filled with 09,4c etc).</code></p>
  
  <p><code>MOV DS,AX</code></p>
  
  <p><code>MOV ES,AX</code></p>