title: IBM Mainframe Assembler - using MVC with a register displacement
body: <p>I am working on an assignment for a college assembly class. We are using IBM Mainframe PC370 emulator. (Old school, but great starting point)</p>
  
  <p>I always try to go a little beyond the scope of the assignment in order to better my programming skills.</p>
  
  <p>What I am trying to do is to move some character data (WORD) into (CWORD) with a offset of 1 using a register. My hope is to be able to place data into an index based off of the input from a file to determine the placement in an index. </p>
  
  <p>We have been given a file that has a five digit dollar figure in position 1-5 and a two digit month code in position 20-21. I would like to put the month code in a register to determine the offset to add the dollar amount into that position in the index.</p>
  
  <p>The following code is what I have been using to attempt the register offset.</p>
  
  <p>Is this even possible? I have not found anything in the textbook or online that specifically discusses doing this type of thing.</p>
  
  <pre>
           L     R5,1
           MVC   CWORD+0(R5),WORD
           WTO   CWORD
           WTOR  'PRESS ENTER TO EXIT',EXIT
  </pre>
  
  <p>Thank you for your time.
  SUBCAN</p>