Equipment determination (INT 11h)

        Return:
          AX = "equipment flag" bits
            11xx xxxx  xxxx xxxx       Number of printers
            xx1x xxxx  xxxx xxxx       Internal modem installed (Convertible)
            xxx1 xxxx  xxxx xxxx       Game I/O attached
            xxxx 111x  xxxx xxxx       Number of RS232 cards
            xxxx xxx1  xxxx xxxx       Unused
            xxxx xxxx  11xx xxxx       Number of diskette drives
                                       (only if bit 0 = 1)
                                       00 = 1, 01 = 2, 10=3 and 11=4
            xxxx xxxx  xx11 xxxx       Initial video mode
                                            01 = 40x25 color
                                            10 = 80x25 color
                                            11 = 80X25 IBM monochrome
            xxxx xxxx  xxxx 11xx       PC: Number of 16K banks on motherboard
                                       XT: Number of 64K banks on motherboard
                                       AT: Allways 11
                                       PS: Bit 2: Mouse installed
            xxxx xxxx  xxxx xx1x       8087 present
            xxxx xxxx  xxxx xxx1       Diskette drives installed