Flow-control structures: Difference between revisions

In for example Fortran IV, as on the IBM1130, a <code>CALL EXIT</code> stopped the run, which is to say, it "exited" to the operating system. As distinct from STOP which stopped the flow by stopping the cpu. Another no-return was provided by the likes of <code>CALL LINK(PHASE2)</code> where PHASE2 was not a text string in quotes. This caused the flow of execution to abandon the current programme and the operating system would to load and run a programme called PHASE2. Code was loaded from low memory upwards, while storage in COMMON was assigned from high memory downwards and so long as desired data were not damaged by the new load, its processing would continue. Thus, if some data required a great deal of complex analysis and there was insufficient memory available to hold all the data plus all the code, it might be possible to split the processing into PHASE1 and PHASE2, etc.