title: Error: Operation size not specified - NASm
body: <p>I'm working in 16 bit NASM assembly having an issue where my code won't build. The error happens on all the MOV lines here:</p>
  
  <pre><code>  section .bss
    x_coord   RESB 8 ; [x_coord] is the head, [x_coord+2] is the next cell, etc.
    y_coord   RESB 8 ; Same here
    pixel_x  RESB 2  ; Storage for calculations
    pixel_y  RESB 2  ; Storage for calculations
  
     ...
  
  
    MOV [pixel_x], [x_coord]
    MOV [pixel_y], [y_coord]
    CALL DrawPixel
  
    MOV [pixel_x], [x_coord+2]
    MOV [pixel_y], [y_coord+2]
    CALL DrawPixel
  
    MOV [pixel_x], [x_coord+4]
    MOV [pixel_y], [y_coord+4]
    CALL DrawPixel
  
    MOV [pixel_x], [x_coord+6]
    MOV [pixel_y], [y_coord+6]
    CALL DrawPixel
  </code></pre>
  
  <p>I've read that this happens because the assembler doesn't know what size the variables are. I tried <code>MOV [pixel_x], byte [x_coord]</code> suggested by some online post but that gives the same error. I just want to copy the first two bytes of x_coord and y_coord into pixel_x/pixel_y, then the next two, then the next two, then the next two. How can I make this work?</p>
  
  <p>Thanks :)</p>