Sections can contain symbolic references to locations defined in the same or other sections. These references are called external references. External references are normally made by using an address constant (adcon). For program objects, the binder supports adcons that are three, four, and eight bytes in length. A symbol referred to by an external reference must be an external name, the name of an entry point, or the name of a pseudoregister. In modules containing only a single text class, the section (CSECT or common area) name is an implied entry point.
By matching an external reference with an external definition (sometimes called an ‘external label’), the binder resolves references between sections. External references and external labels are called external symbols. External symbols are defined in one section and can be referred to in the same section, or from other sections.
- Two-byte relative immediate references are supported within a segment, but are not supported across separate segments.
- Four-byte relative immediate references are supported except if either segment is RMODE 64.
