/FD
       /PD

    Defines a symbol as a function descriptor (FD) or procedure
    descriptor (PD). It also defines the routine address symbol
    corresponding to the defined symbol (the routine address symbol
    has the same name as the defined symbol, only with _C appended to
    the symbol name). /FD and /PD are completely interchangeable. SDA
    interprets them based on the architecture of the system or dump
    being analyzed.