o  The low quadword contains the specified constant value.

    o  The high quadword contains the sign extension of the specified
       constant value. That is, the high quadword contains 0 if the
       specified value is positive, and it contains all bits set to 1
       if the specified value is negative.

    o  You can only use this directive within data or mixed psects
       (psects that have either the NOEXE or MIX attributes).

    o  If automatic data alignment is enabled, this directive aligns
       the current location counter to an octaword (128-bit) boundary
       before allocating storage.