/B64[=value]
  /NOB64[=value] (D)

   This qualifier is only valid for the languages BLISS and BLISSF.

   The default extension for the output file is .R64 if /B64 is specified
   and .R32 otherwise.

   The word size used in BITFIELDs is 64 bits if /B64 is specified and
   32 bits otherwise.

   The name used for conditional compilation changes from BLISS or BLISSF
   to BLISS64 or BLISSF64, respectively.

   The value will be ignored.

   You cannot specify the qualifiers /B64 and /VAX together.