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

    Generates 128 bits (16 bytes) of binary data.

      .OCTA literal
      .OCTA symbol

    literal

    Any constant value.  This value can be preceded by ^O, ^B, ^X, or
    ^D to  specify  the  radix  as  octal,  binary, hexadecimal, or
    decimal, respectively; or it can be preceded by  ^A  to  specify
    ASCII  text. Decimal is the default radix.

    symbol

    A symbol defined elsewhere in the program.  This symbol results in
    a sign-extended, 32-bit value being stored in an octaword.

    It does not evaluate expressions and that it accepts only one
    value.