INT 10 - VIDEO - GET CURSOR POSITION AND SIZE
        AH = 03h
        BH = page number
            0-3 in modes 2&3
            0-7 in modes 0&1
            0 in graphics modes
Return: AX = 0000h (Phoenix BIOS)
        CH = start scan line
        CL = end scan line
        DH = row (00h is top)
        DL = column (00h is left)
Notes:  a separate cursor is maintained for each of up to 8 display pages
        many ROM BIOSes incorrectly return the default size for a color display
          (start 06h, end 07h) when a monochrome display is attached
SeeAlso: AH=02h