Calculation of PI - CIS COBOL example program

This program simply displays on the screen the mathematical constant PI to 12 decimal places and is the basic screen test for CIS COBOL DISPLAY.

       IDENTIFICATION DIVISION.
       PROGRAM-ID. PI-CALC.
       AUTHOR. PF/TR.
      *
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       SOURCE-COMPUTER.
       OBJECT-COMPUTER.
       SPECIAL-NAMES. CONSOLE IS CRT.
      *
       DATA DIVISION.
       WORKING-STORAGE SECTION.
      *
       01  SCREEN PIC X(1920).
      *
       01  DI-1 REDEFINES SCREEN.
           02 FILLER PIC X(160).
           02 DI-TX1 PIC X(160).
           02 DI-TX2 PIC X(13).
           02 DI-TERM PIC X(15).
           02 FILLER PIC X(136).
           02 DI-TX3 PIC X(6).
           02 DI-PI PIC X(15).
           02 FILLER PIC X(1415).
      *
       01  DI-2 REDEFINES SCREEN.
           02 FILLER PIC X(333).
           02 DI-TERM2 PIC X(15).
           02 FILLER PIC X(142).
           02 DI-PI2 PIC X(15).
           02 FILLER PIC X(1415).
      *
       01  WORK-AREA.
           02 PI PIC S9V9(14).
           02 TERM PIC S9V9(14).
           02 W PIC S9V9(14).
           02 N PIC 9999.
           02 N1 PIC 9999.
           02 N2 PIC 9999.
           02 ED PIC -9.9(12).
      *
       01  CONSTANTS.
           02 TX1 PIC X(17) VALUE "CALCULATION OF PI".
           02 TX2 PIC X(12) VALUE "NEXT TERM IS".
           02 TX3 PIC X(5) VALUE "PI IS".
      *
       PROCEDURE DIVISION.
       LA-START.
           DISPLAY SPACE.
           MOVE SPACE TO SCREEN.
           MOVE TX1 TO DI-TX1.
           MOVE TX2 TO DI-TX2.
           MOVE TX3 TO DI-TX3.
           MOVE 0.5 TO ED.
           MOVE ED TO DI-TERM.
           MOVE 3 TO ED.
           MOVE ED TO DI-PI.
           DISPLAY DI-1.
           MOVE 0.5 TO PI.
           MOVE 0.5 TO TERM.
           MOVE 3 TO N.
       LOOP.
           MOVE N TO N2.
           SUBTRACT 2 FROM N2.
           MULTIPLY N2 BY N2.
           MULTIPLY N2 BY TERM.
           MOVE N TO N1.
           SUBTRACT 1 FROM N1.
           MULTIPLY N BY N1.
           MULTIPLY 4 BY N1.
           DIVIDE N1 INTO TERM.
           IF TERM < 0.0000000000001 THEN GO TO HALT.
           ADD TERM TO PI.
           MOVE PI TO W.
           MULTIPLY 6 BY W.
           MOVE W TO ED.
           MOVE ED TO DI-PI2.
           MOVE TERM TO ED.
           MOVE ED TO DI-TERM2.
           DISPLAY DI-2.
           ADD 2 TO N.
           IF N < 100 GO TO LOOP.
       HALT.
           STOP RUN.