External symbol attribute directive

    Format

      .EXTERNAL  symbol-list

      .EXTRN  symbol-list

1  –  Parameter

 symbol-list

    A list of symbol names separated by commas.

2  –  Description

    .EXTERNAL indicates that the specified symbols are external; that
    is, the symbols are defined in another object module.

3  –  Notes

    o  The alternate form of .EXTERNAL is .EXTRN.

4  –  Example

             .EXTERNAL B    ; B is defined in another module
                .
                .
                .
        A::  .ADDRESS B    ; Its address is stored here