Prolog and epilog code

The primary functions of prolog code are:
  • To save the calling function’s general-purpose registers in the calling function’s save area.
  • To obtain the dynamic storage area for this function.
  • To chain this function’s save area to the calling function’s save area, in accordance with the MVS™ linkage convention.
The primary functions of epilog code are:
  • To relinquish this function’s dynamic storage area.
  • To restore the calling function’s general-purpose registers.
  • To return control to the calling function.
Note: AR-mode functions require additional prolog and epilog functions. See AR-mode programming support for details.