COMMENT        PROCEDURE - MODE-CHANGE,                                 00000100
               CUBE LIBRARY NUMBER IS P000001.                          00000200
               THIS VERSION DATED 2/1/67;                               00000300
PROCEDURE MODECH (FILEN,L1,L2);FILE FILEN;LABEL L1,L2;BEGIN BOOLEAN BULL00000400
;STREAM PROCEDURE TESTRED(FILENAME,BULL);BEGIN SI~FILENAME;SKIP 29 SB;DI00000500
~BULL;SKIP 47 DB;IF SB THEN DS~1 SET ELSE DS~1 RESET; END; TESTRED(FILEN00000600
,BULL); IF BULL THEN GO TO L1 ELSE GO TO L2; END;                       00000700