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Invoking Sub-routines

High Level Language programmers are probably familiar with the concepts of Static Linkage versus Dynamic Linkage as methods of invoking sub-routines.

The same concepts apply within Assembler, but the terminology is more like that within CICS/TS, as although there is a CALL macro, there are also LINK, LOAD and XCTL macros.

Opposite are links to pages which illustrate the methods available in Assembler.

The different methods of invoking sub-routines

Select this link for an explanation on the differences between the methods.

Select the macro name below for more information.

CALL - Static Linkage

LINK - Dynamic Linkage

LOAD + CALL - Dynamic Linkage

XCTL - Dynamic Linkage NO RETURN

The above relates to External Sub-routines. Structured programming concepts are largely absent in Assembler so the equivalent of COBOL PARAGRAPHS or SECTIONS and PLI Internal PROCs are npt readily available, the best Assembler has to offer are the BAS/BASR and BR instruction combinations.