.CREF            Enable Cross-Reference Listings                    Directive

  .CREF

    Enables the generation of cross-references listings of labels,
    variables, and symbols.

       Notes:     This directive does not tell the assembler to
                  produce a cross-reference listing, but if a cross-
                  reference listing is specified, it will enable the
                  generation of cross-referenced labels, variables, and
                  symbols, whereas when a .XCREF directive is
                  encountered, all references (labels, variables, and
                  symbols) will not be cross-referenced until a .CREF is
                  encountered.