Int 21 Fn 02  - DOS 1+ - Write Character To Standard Output                [D]

   AH = 02h
   DL = character to write

Return: AL = last character output (despite the official docs which state
       nothing is returned) (at least DOS 3.3-5.0)

Notes:  Break are checked, and INT 23 executed if pressed
   standard output is always the screen under DOS 1.x, but may be
     redirected under DOS 2+
   the last character output will be the character in DL unless DL=09h
     on entry, in which case AL=20h as tabs are expanded to blanks

See Also: AH=06h,AH=09h