INT 15 - EISA SYSTEM ROM - READ SLOT CONFIGURATION INFORMATION
        AX = D800h
        CL = slot number (including embedded and virtual)
Return: CF clear if successful
            AH = 00h
        CF set on error
            AH = error code
                80h invalid slot number
                82h EISA CMOS corrupt
                83h empty slot
                86h invalid BIOS-FW function call
                87h invalid system configuration
        AL bit flags
            bit 7: set if duplicate IDs
                6: set if product ID readable
              4,5: slot type (00=expansion, 01=embedded, 10=virtual device)
              0-3: duplicate ID number if bit 7 set
        BH = major revision level of configuration utility
        BL = minor revision level of configuration utility
        CX = checksum of configuration file
        DH = number of device functions
        DL = combined function information byte
        SI:DI = 4-byte compressed ID (DI = bytes 0&1, SI = bytes 2&3)
Note:   call with AL=80h if using 32-bit CS addressing mode instead of 16-bit
SeeAlso: AX=D804h