INT 10 - VIDEO - SELECT VIDEO DAC COLOR PAGE (VGA)
        AX = 1013h
        BL = subfunction
            00h select paging mode
                BH = 00h select 4 blocks of 64
                BH = 01h select 16 blocks of 16
            01h select page
                BH = page number (00h to 03h) or (00h to 0Fh)
Note:   this function is not valid in mode 13h