Int 21 Fn A5  - Attachmate Extra! - Get Host Window Cursor Position        [I]

   AH = A5h
   AL = window number (1-4=host B-E)

Return: BX = cursor position (80 * row + column, where 0:0 is upper left)

Note:  if the host window is configured with the Extended Attribute (EAB)
     feature, multiply the cursor position by 2 to obtain the byte offset
     into the display buffer

See Also: AH=A4h