Keyword arguments allow a macro call to specify the arguments
    in any order. In this case, the macro call must specify the
    same formal argument names that appear in the macro definition.
    Keyword arguments are useful when a macro definition has more
    formal arguments than necessary in the call.

    In any one macro call, it is good practice to specify the
    arguments as either all positional arguments or all keyword
    arguments. For example, the following macro definition specifies
    three arguments:

    .MACRO  STORE   ARG1,ARG2,ARG3
    .LONG   ARG1
    .WORD   ARG3
    .BYTE   ARG2
    .ENDM   STORE

    The following macro call specifies keyword arguments:

    STORE   ARG3=27+5/4,ARG2=5,ARG1=SYMBL
    .LONG   SYMBL
    .WORD   27+5/4
    .BYTE   5

    Because the keywords are specified in the macro call, the
    arguments in the macro call need not be given in the order they
    were listed in the macro definition.

    Positional and keyword arguments may be mixed. Usually,
    positional arguments are placed before keyword arguments. For
    example:

    .MACRO  STORE   ARG1,ARG2,ARG3=27+5/4
    .LONG   ARG1
    .BYTE   ARG2
    .WORD   27+5/4
    .ENDM   STORE

                                   NOTE

       Keyword arguments are not counted when positional arguments
       are parsed. This means that when positional and keyword
       arguments are used in the same macro, one argument can be
       specified twice. The last value specified for the argument
       is used.