VMS Help MACRO, VAX MACRO Assembler, Instructions, BUGx  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Purpose:        bugcheck
    Operation:      {fault to report error}
    C. Codes:       not affected
    Exceptions:     Reserved instruction
    Opcodes:        FEFF  BUGW     Bugcheck with word message identifier
                    FDFF  BUGL     Bugcheck with longword message id
    Description:    The hardware treats these opcodes as RESERVED to
                    Digital and faults. The VAX/VMS operating system
                    treats these as requests to report software-detected
                    errors. The in-line message identifier is zero
                    extended to a longword and interpreted as a
                    condition value. If the process is privileged to
                    report bugs, a log entry is made. If the process is
                    not privileged, a reserved instruction is signalled.