INT 10 - VIDEO - Paradise VGA, AT&T VDC600 - EXTENDED FUNCTIONS
        AX = 007Fh
        BH = function
            00h  set VGA operation
            01h  set non-VGA operation
                color modes (0,1,2,3,4,5,6) will set non-VGA CGA operation
                monochrome mode 7 will set non-VGA MDA/Hercules operation
            02h  query mode status
                Return: BL = 00h if operating in VGA mode, 01h if non-VGA mode
                        CH = total video RAM size in 64k byte units
                        CL = video RAM used by the current mode
            03h  lock current mode
                allows current mode (VGA or non-VGA) to survive re-boot
            04h  enter CGA mode (AT&T VDC600 only)
            05h  enter MDA mode (AT&T VDC600 only)
            0Ah,0Bh,0Ch,0Dh,0Eh,0Fh  WRITE PARADISE REGISTERS 0,1,2,3,4,5
                (port 03CEh indices 0Ah,0Bh,0Ch,0Dh,0Eh,0Fh)
                BL = value to set in the paradise register
            1Ah,1Bh,1Ch,1Dh,1Eh,1Fh READ PARADISE REGISTERS 0,1,2,3,4,5
                (port 03CEh indices 0Ah,0Bh,0Ch,0Dh,0Eh,0Fh)
                Return: BL = value of the paradise register
                        BH = 7Fh if successful
Return: AL = 7Fh if successful (AT&T VDC600)