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  Service 03H (decimal 3) is the opposite of services 01H and 02H. When you
  specify the page number in BH, the ROM BIOS reports the cursor size by
  returning the starting scan line in CH and the ending scan line in CL. In
  addition, it reports the cursor position by returning the row in DH and
  the column in DL. (See Figure 9-4.)

  Service Number           Returns
  --------------------------------------------------------------------------
  AH = 03H                 BH = page number (set to 0 in graphics modes)
                           DH = row number
                           DL = column number
                           CH = starting scan line of cursor
                           CL = ending scan line of cursor
  --------------------------------------------------------------------------

  Figure 9-4.  Values reported by video service 03H.