INT 49 - MAGic v1.23+ - SET TEXT MODE MAGNIFICATION SIZE
        AX = 0008h
        BX = scaling factor (01h=1.4 times, 02h, 04h, 06h, 08h, 09h=12 times)
Return: AX = status
            0000h successful
            FFFBh scaling factor only available in MAGic Deluxe
            FFFCh already in magnified state, can't set size
Notes:  this call specifies the amount a subsequent call to AX=0001h should
          magnify the display
        scaling factors greater than 2 are only available in MAGic Deluxe