A direct assignment statement equates a symbol to a specific
    value. Unlike a symbol that you use as a label, you can redefine
    a symbol defined with a direct assignment statement as many times
    as you want.
    FORMATS

    symbol=expression

    symbol==expression

    symbol=quoted-literal

 symbol

    A user-defined symbol.

 expression

    An expression that does not contain any undefined symbols or
    forward references. The result must be either an absolute or
    relocatable value, whose value can be determined at the current
    point in the assembly. This form defines a numeric symbol.

    The format with a single equal sign (=)  defines a local symbol,
    and the format with a double equal sign (==) defines a global
    symbol.

    The following three syntactic rules apply to direct assignment
    statements:

    o  An equal sign (=)  or double equal sign (==) must separate
       the symbol from the expression that defines its value. Spaces
       preceding or following the direct assignment operators have no
       significance in the resulting value.

    o  Only one symbol can be defined in a single direct assignment
       statement.

    o  A direct assignment statement can be followed only by a
       comment field.

    For best results, Digital recommends you place the symbol in a
    direct assignment statement in the label field. For example:

    A == 1                  ; The symbol 'A' is globally
                            ;   equated to the value 1

    B = A@5                 ; The symbol 'B' is equated
                            ;   to 1@5 or 32(dec)

    C = 127*10              ; The symbol 'C' is equated
                            ;   to 1270(dec)

    D = ^X100/^X10          ; The symbol 'D' is equated
                            ;   to 10(hex)

 quoted-literal

    A literal within double quotes. This form defines a lexical
    string symbol. You can only use lexical string symbols with
    lexical string operators.