Return: AX = "equipment flag" bits
            0       diskette installed
            1       8087 present
            2,3     always = 11
            4,5     initial video mode
                    01 = 40x25 COLOR
                    10 = 80x25 COLOR
                    11 = 80X25 IBM monochrome
            6,7     number of diskette drives (only if bit 0 = 1)
                    00 = 1, 01 = 2
            8       0 = dma present, 1= no dma on system (PCjr?)
            9,10,11 number of RS232 cards
            12      game I/O attached
            13      serial printer installed (IBM-PCjr)
                    internal modem installed (Convertible)
            14,15   number of printers
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