      PROGRAM EDR
C
C EDR HEADER UNPACKING PROGRAM WRITTEN TO BE IMPLEMENTED UNDER VMS
C ARCHITECTURE.  EDR DATA IS WRITTEN FOR THE IBM 360 ARCHITECTURE.
C
      LOGICAL*1 REC(11280)
      CHARACTER ANS*1,TFLAG*4,DSN*50
      INTEGER*2 RECLEN,EDRTIME(6),SCETIME(6),SERTIME(6),EERTIME(6),
     &          TIME(6)
      REAL*8 NEWTIME,OLDTIME,REALTIME,T1,T2
C
      INCLUDE 'UNPACK.INC'
C
      TFLAG = 'SCET'
C
C CREATE BIT FLIP TRANSLATION TABLE FOR LOGICAL*1 WORDS.  
C ASSIGN FLIP(0:255) THE BIT FLIP INVERSE OF VALUES 0 TO 255.
C
      DO J=0,255
       DO I=0,7
        CALL MOVBIT(J, I, 1, FLIP(J), 7-I)
       END DO
      END DO
C
C OPEN BINARY EDR INPUT DATASET
C
      WRITE(6,*) 
      WRITE(6,*) 'ENTER EDR INPUT DSN '
      READ(5,'(Q,A)') LEN,DSN
      WRITE(6,*) 
      WRITE(6,*) DSN
      WRITE(6,*) 
      OPEN(50,FILE=DSN,STATUS='OLD',FORM='FORMATTED',
     &     RECORDTYPE='VARIABLE',RECL=8191,READONLY)
C
      WRITE(6,*) 
      WRITE(6,*) 'ENTER EDR OUTPUT DSN '
      READ(5,'(Q,A)') LEN,DSN
      WRITE(6,*) 
      WRITE(6,*) DSN
      WRITE(6,*) 
      OPEN(51,FILE=DSN,STATUS='NEW',FORM='UNFORMATTED',
     &     RECORDTYPE='VARIABLE',RECL=8191)
C
      WRITE(6,*)
      WRITE(6,*) 'ENTER START TIME'
      WRITE(6,*)
      WRITE(6,*) 'YY/DDD/HH:MM:SS:FFF'
      READ(5,'(I2,1X,I3,3(1X,I2),1X,I3)',ERR=3) TIME
    3 CONTINUE
      T1 = REALTIME(TIME)
      WRITE(6,*)
      WRITE(6,*)
      WRITE(6,*) 'ENTER STOP TIME'
      WRITE(6,*)
      WRITE(6,*) 'YY/DDD/HH:MM:SS:FFF'
      READ(5,'(I2,1X,I3,3(1X,I2),1X,I3)',ERR=4) TIME
    4 CONTINUE
      T2 = REALTIME(TIME)
C
      OLDTIME = 0.0D0
      NCNT = 0
   10 CONTINUE
       READ(50,'(Q,<RECLEN>A1)',END=100) RECLEN,(REC(I),I=1,RECLEN)
       NCNT = NCNT + 1
       CALL UNHEAD(REC)
       CALL GETTIME(TFLAG,SERTIME,EERTIME,SCETIME,EDRTIME)
       NEWTIME = REALTIME(EDRTIME)
C
       IF ( RECID.NE.4 ) GOTO 10
       IF ( RECID.EQ.4 .AND. NEWTIME.LT.T1 ) GOTO 10
       IF ( RECID.EQ.4 .AND. NEWTIME.GT.T2 ) GOTO 100
C
       CALL DISPLAY(RECLEN,NCNT,TFLAG,EDRTIME)
       IF ( OLDTIME.GT.NEWTIME .AND. RECID.EQ.4 ) THEN
        WRITE(6,*)
        WRITE(6,*) 'RETROGRADE TIME'
        WRITE(6,*) '   T(-1) = ',OLDTIME
        WRITE(6,*) '   T(0) = ',TIME
        WRITE(6,*)
        WRITE(6,*) 'REMOVE (Y/N)'
        READ(5,'(A)') ANS
        IF ( ANS.EQ.'Y' .OR. ANS.EQ.'y' ) GOTO 10
       END IF
       OLDTIME = NEWTIME
       WRITE(51) (REC(I),I=1,RECLEN)
      GOTO 10
  100 CONTINUE
      WRITE(6,*) 
      WRITE(6,*) NCNT,' TOTAL EDR''S'
      WRITE(6,*) 
C
      STOP
      END
******************************************************************
C
C DISPLAY KEY VALUES FROM UNPACKED EDR
C
      SUBROUTINE DISPLAY(RECLEN,NCNT,TFLAG,TIME)
      INTEGER*2 RECLEN,TIME(6)
      CHARACTER*4 TFLAG,EX(0:15)
      CHARACTER*6 DM(0:31)
      CHARACTER*7 DDT(32:48)
C
      INCLUDE 'UNPACK.INC'
C
      DATA EX/'***','CRS','IRIS','LECP','MAG','PLS','PPS','PRA','PWS',
     &        'UVS','RSS','ENG','***','ISR','MR','DMR'/
      DATA DM/'ENG','CR-2','CR-3','CR-4','CR-5','CR-6','CR-7','CR-1',
     &        'GS-10A','***','GS-3','***','GS-7','***','GS-6','GS-4',
     &        '***','GS-2','***','***','***','***','OC-2','OC-1',
     &        'CR-5A','GS-10','GS-8','***','***','UV-5A','***','***'/
      DATA DDT/'IRIS','CRS','LECP','MAG','PLS','PPS','PRA','PWS','UVS',
     &         'ISR','DCOM','MON 5-8','ENGS','ENGE','DCMS','ENGC',
     &         'MON 5-9'/
C
      WRITE(6,900) NCNT,RECNUM,RECLEN,PROJID,EX(RECID),SCID,
     &             TFLAG,TIME,DM(DATMOD),DDT(DRSDAT)
      RETURN
  900 FORMAT(1X,I5,1X,I5,1X,I5,' BYTES',1X,A3,1X,A4,1X,I2,1X,A4,
     &       1X,I2,1X,I3.3,3(1X,I2.2),1X,I3.3,1X,A6,1X,A7)
      END
******************************************************************
*
*	TITLE:  UNPACK VOYAGER 60 WORD EDR HEADER
*
*	FILE NAME:  UNHEAD.FOR
*
*	PURPOSE:  TO UNPACK THE HEADER BLOCK
*
*	HISTORY:
*
*	AUTHOR            DATE             CHANGE
*	--------          ----             ------
*	S. J. KEMPLER     8/12/85          ORIGINAL CODE
*       S. B. KRAMER      9/27/92          MODIFIED FOR VIM-5 MODE
*       S. B. KRAMER     10/26/93          MODIFIED FOR ALL MODES
*
*	CALLING SEQUENCE:  SUBROUTINE UNHEAD(INBUF)
*
*	MODULES REFERENCED:
*
*		MOVBIT
*
*	COMMON AREAS:
*
*		SEE UNPACK.INC FOR COMMON AREA DEFINITIONS
*
*	PDL:
*
*		GET HEADER BLOCK FROM EDR RECORD
*		CALL MOVBIT TO LOAD DATMOD WITH DATA MODE
*		CALL MOVBIT TO LOAD MOD60 WITH MOD 60 COUNT WORD
*		LOAD PROJID WITH THE 3 CHARACTER PROJECT ID
*		CALL MOVBIT TO LOAD ALL OTHER ITEMS OF THE HEADER FIELD 
*                INTO INDIVIDUAL I*2 VARIABLES
*		RETURN
*
******************************************************************* 
C
      SUBROUTINE UNHEAD(INBUF)
C
      LOGICAL*1 INBUF(11280),LPROJ(3)
C
      INCLUDE 'UNPACK.INC'
C
      EQUIVALENCE (PROJID,LPROJ(1))
C
C ASSIGN FIRST 240 BYTES OF EDR RECORD TO HEADER ARRAY (ALL MODES)
C
      DO I = 1,240
       HEAD(I) = INBUF(I)
      END DO
C
C     LPROJ(1) = HEAD(1)
C     LPROJ(2) = HEAD(2)
C     LPROJ(3) = HEAD(3)
C
C     ISTAT = LIB$TRA_EBC_ASC(PROJID,PROJID)
C
C IDENTIFY MARINER JUPITER SATURN (MJS) PROJECT ID
C
C     IF (PROJID.NE.'MJS') RETURN
C
C SEARCH FOR DECIMAL EQUIVALENT OF EBCDIC 'MJS'
C
      IF ( ZEXT(HEAD(1)).EQ.212 .AND.
     &     ZEXT(HEAD(2)).EQ.209 .AND.
     &     ZEXT(HEAD(3)).EQ.226 ) THEN
       PROJID = 'MJS'
      ELSE
       RETURN
      END IF
C
C ERROR IN KEMPLER'S DECOMMUTATION REVERSES RECID AND SCID 
C CORRECTED FOR VIM-5 PROCESSING (SBK - 10/8/92)
C
      HEAD(4) = FLIP(ZEXT(HEAD(4)))
      RECID = 0
      CALL MOVBIT(  HEAD,  24,  1,  RECID,   3)
      CALL MOVBIT(  HEAD,  25,  1,  RECID,   2)
      CALL MOVBIT(  HEAD,  26,  1,  RECID,   1)
      CALL MOVBIT(  HEAD,  27,  1,  RECID,   0)
      SCID = 0
      CALL MOVBIT(  HEAD,  28,  1,   SCID,   3)
      CALL MOVBIT(  HEAD,  29,  1,   SCID,   2)
      CALL MOVBIT(  HEAD,  30,  1,   SCID,   1)
      CALL MOVBIT(  HEAD,  31,  1,   SCID,   0)
C
      RECNUM = 0
      CALL MOVBIT(  HEAD,  40,  8, RECNUM,   0)
      CALL MOVBIT(  HEAD,  32,  8, RECNUM,   8)
      DATMOD = 0
      CALL MOVBIT(  HEAD,  48,  8, DATMOD,   0)
C
      HEAD(8) = FLIP(ZEXT(HEAD(8)))
      EEXTFL = 0
      CALL MOVBIT(  HEAD,  56,  1, EEXTFL,   1)
      CALL MOVBIT(  HEAD,  57,  1, EEXTFL,   0)
      SCPLAB = 0
      CALL MOVBIT(  HEAD,  58,  1, SCPLAB,   0)
      RECTIM = 0
      CALL MOVBIT(  HEAD,  59,  1, RECTIM,   4)
      CALL MOVBIT(  HEAD,  60,  1, RECTIM,   3)
      CALL MOVBIT(  HEAD,  61,  1, RECTIM,   2)
      CALL MOVBIT(  HEAD,  62,  1, RECTIM,   1)
      CALL MOVBIT(  HEAD,  63,  1, RECTIM,   0)
C
      ERTSHR = 0
      CALL MOVBIT(  HEAD,  72,  8, ERTSHR,   0)
      CALL MOVBIT(  HEAD,  64,  8, ERTSHR,   8)
      ERTSSC = 0
      CALL MOVBIT(  HEAD,  88,  8, ERTSSC,   0)
      CALL MOVBIT(  HEAD,  80,  8, ERTSSC,   8)
      ERTSML = 0
      CALL MOVBIT(  HEAD, 104,  8, ERTSML,   0)
      CALL MOVBIT(  HEAD,  96,  8, ERTSML,   8)
      YEAR1 = 0
      CALL MOVBIT(  HEAD, 112,  8,  YEAR1,   0)
C
      HEAD(16) = FLIP(ZEXT(HEAD(16)))
      DATSRC = 0
      CALL MOVBIT(  HEAD, 120,  1, DATSRC,   1)
      CALL MOVBIT(  HEAD, 121,  1, DATSRC,   0)
      GOLAY = 0
      CALL MOVBIT(  HEAD, 122,  1,  GOLAY,   1)
      CALL MOVBIT(  HEAD, 123,  1,  GOLAY,   0)
      SEGNUM = 0
      CALL MOVBIT(  HEAD, 124,  1, SEGNUM,   3)
      CALL MOVBIT(  HEAD, 125,  1, SEGNUM,   2)
      CALL MOVBIT(  HEAD, 126,  1, SEGNUM,   1)
      CALL MOVBIT(  HEAD, 127,  1, SEGNUM,   0)
C
      ERTEHR = 0
      CALL MOVBIT(  HEAD, 136,  8, ERTEHR,   0)
      CALL MOVBIT(  HEAD, 128,  8, ERTEHR,   8)
      ERTESC = 0
      CALL MOVBIT(  HEAD, 152,  8, ERTESC,   0)
      CALL MOVBIT(  HEAD, 144,  8, ERTESC,   8)
      ERTEML = 0
      CALL MOVBIT(  HEAD, 168,  8, ERTEML,   0)
      CALL MOVBIT(  HEAD, 160,  8, ERTEML,   8)
      YEAR2 = 0
      CALL MOVBIT(  HEAD, 176,  8,  YEAR2,   0)
      SWVERS = 0
      CALL MOVBIT(  HEAD, 184,  8, SWVERS,   0)
      SCETHR = 0
      CALL MOVBIT(  HEAD, 200,  8, SCETHR,   0)
      CALL MOVBIT(  HEAD, 192,  8, SCETHR,   8)
      SCETSC = 0
      CALL MOVBIT(  HEAD, 216,  8, SCETSC,   0)
      CALL MOVBIT(  HEAD, 208,  8, SCETSC,   8)
      SCETML = 0
      CALL MOVBIT(  HEAD, 232,  8, SCETML,   0)
      CALL MOVBIT(  HEAD, 224,  8, SCETML,   8)
      YEAR3 = 0
      CALL MOVBIT(  HEAD, 240,  8,  YEAR3,   0)
C
      HEAD(32) = FLIP(ZEXT(HEAD(32)))
      SCEVFL = 0
      CALL MOVBIT(  HEAD, 248,  1, SCEVFL,   3)
      CALL MOVBIT(  HEAD, 249,  1, SCEVFL,   2)
      CALL MOVBIT(  HEAD, 250,  1, SCEVFL,   1)
      CALL MOVBIT(  HEAD, 251,  1, SCEVFL,   0)
      CORRFL = 0
      CALL MOVBIT(  HEAD, 252,  1, CORRFL,   3)
      CALL MOVBIT(  HEAD, 253,  1, CORRFL,   2)
      CALL MOVBIT(  HEAD, 254,  1, CORRFL,   1)
      CALL MOVBIT(  HEAD, 255,  1, CORRFL,   0)
C
      MOD216 = 0
      CALL MOVBIT(  HEAD, 264,  8, MOD216,   0)
      CALL MOVBIT(  HEAD, 256,  8, MOD216,   8)
      MOD60 = 0
      CALL MOVBIT(  HEAD, 272,  8,  MOD60,   0)
      LINCNT = 0
      CALL MOVBIT(  HEAD, 288,  8, LINCNT,   0)
      CALL MOVBIT(  HEAD, 280,  8, LINCNT,   8)
      TELRAT = 0
      CALL MOVBIT(  HEAD, 296,  8, TELRAT,   0)
      EFFRAT = 0
      CALL MOVBIT(  HEAD, 304,  8, EFFRAT,   0)
      FORMID = 0
      CALL MOVBIT(  HEAD, 312,  8, FORMID,   0)
      BERTOL = 0
      CALL MOVBIT(  HEAD, 320,  8, BERTOL,   0)
      DSNCON = 0
      CALL MOVBIT(  HEAD, 328,  8, DSNCON,   0)
      RECAGC = 0
      CALL MOVBIT(  HEAD, 344,  8, RECAGC,   0)
      CALL MOVBIT(  HEAD, 336,  8, RECAGC,   8)
      DSNNUM = 0
      CALL MOVBIT(  HEAD, 352,  8, DSNNUM,   0)
      EBEC = 0
      CALL MOVBIT(  HEAD, 376,  8,   EBEC,   0)
      CALL MOVBIT(  HEAD, 368,  8,   EBEC,   8)
      SYMSNR = 0
      CALL MOVBIT(  HEAD, 392,  8, SYMSNR,   0)
      CALL MOVBIT(  HEAD, 384,  8, SYMSNR,   8)
      DECSNR = 0
      CALL MOVBIT(  HEAD, 408,  8, DECSNR,   0)
      CALL MOVBIT(  HEAD, 400,  8, DECSNR,   8)
      PHYSRN = 0
      CALL MOVBIT(  HEAD, 424,  8, PHYSRN,   0)
      CALL MOVBIT(  HEAD, 416,  8, PHYSRN,   8)
C
C 8 BIT DATA QUALITY STATUS WORD//8 BIT DATA QUALITY INDICATOR
C
      DO 10 I=1,10
         J = (I-1) * 16
         DQSW(I) = 0
         CALL MOVBIT(  HEAD, 432+J,  8, DQSW(I),   0)
         DQI(I) = 0
         CALL MOVBIT(  HEAD, 440+J,  8,  DQI(I),   0)
  10  CONTINUE
C
C UNPACK 4 BIT DATA PRESENCE INDICATORS (80 MF MAX)
C CR-7 AND VIM-5 MODES
C
      IF ( MODE(IMODE).NE.13 .AND. MODE(IMODE).NE.9 ) GOTO 20
      DO 20 I=1,40
         J = (I-1) * 8
         K = I*2 - 1
         L = I*2
         DPI(K) = 0
         DPI(L) = 0
         CALL MOVBIT(  HEAD, 592+J,  4, DPI(L),   0)
         CALL MOVBIT(  HEAD, 596+J,  4, DPI(K),   0)
  20  CONTINUE
C
C UNPACK 8 BIT DATA PRESENCE INDICATORS (150 MF MAX)
C CR-1 THROUGH CR-6 MODES
C
      IF ( MODE(IMODE).LT.1 .OR. MODE(IMODE).GT.6 ) GOTO 30
      DO 30 I=1,150
       J = (I-1)*8
       DPI(I) = 0
       CALL MOVBIT(  HEAD, 592+J,  8, DPI(I),   0)
  30  CONTINUE
C
C UNPACK 8 BIT DATA PRESENCE INDICATORS AND 8 BIT GOLAY CORRECTION
C INDICATORS (80 MF MAX)
C GS-3 MODE
C
      IF ( MODE(IMODE).NE.0 ) GOTO 40
      DO 40 I=1,80
       J = (I-1)*16
       DPI(I) = 0
       CALL MOVBIT(  HEAD, 592+J,  8, DPI(I),   0)
       GCI(I) = 0
       CALL MOVBIT(  HEAD, 600+J,  8, GCI(I),   0)
  40  CONTINUE
C
C FIELDS GCI, DPIRIS, GPIRIS ARE NOT USED IN VIM-5 MODE.
C THEREFORE BITS 892 - 1887 ARE SPARES.
C
      DRSDAT = 0
      CALL MOVBIT(  HEAD, 1888,  8, DRSDAT,   0)
      GCBEC = 0
      CALL MOVBIT(  HEAD, 1896,  8,  GCBEC,   0)
      GBITES = 0
      CALL MOVBIT(  HEAD, 1912,  8, GBITES,   0)
      CALL MOVBIT(  HEAD, 1904,  8, GBITES,   8)
C
      RETURN
      END
******************************************************************
      SUBROUTINE CONSEC(SOH,TIME)
C
C CONVERT I*2 SECONDS OF HOUR INTO MINUTES AND SECONDS.
C
      INTEGER*2 SOH,TIME(6)
      TIME(4) = INT(SOH/60.0)
      TIME(5) = NINT(((SOH/60.0)-TIME(4))*60.0)
      RETURN
      END
******************************************************************
      SUBROUTINE CONHOUR(HOY,TIME)
C
C CONVERT I*2 HOUR OF YEAR INTO DAYS AND HOURS.
C
      INTEGER*2 HOY,TIME(6)
      TIME(2) = INT(HOY/24.0)
      TIME(3) = NINT(((HOY/24.0)-TIME(2))*24.0)
      RETURN
      END
******************************************************************
      SUBROUTINE GETTIME(TFLAG,SERTIME,EERTIME,SCETIME,EDRTIME)
C
C CONVERT EDR TIME TAGS TO CALENDAR UNITS
C
      CHARACTER*4 TFLAG
      INTEGER*2 SERTIME(6),EERTIME(6),SCETIME(6),EDRTIME(6)
C
      INCLUDE 'UNPACK.INC'    
C
      SERTIME(1) = YEAR1
      CALL CONHOUR(ERTSHR,SERTIME)
      CALL CONSEC(ERTSSC,SERTIME)
      SERTIME(6) = ERTSML
C
      EERTIME(1) = YEAR2
      CALL CONHOUR(ERTEHR,EERTIME)
      CALL CONSEC(ERTESC,EERTIME)
      EERTIME(6) = ERTEML
C
      SCETIME(1) = YEAR3
      CALL CONHOUR(SCETHR,SCETIME)
      CALL CONSEC(SCETSC,SCETIME)
      SCETIME(6) = SCETML
C
C SELECT TIME TYPE FOR EDR TIME
C
      IF (TFLAG.EQ.'ERTS') THEN
       DO I = 1,6
        EDRTIME(I) = SERTIME(I)
       END DO
      ELSE IF (TFLAG.EQ.'ERTE') THEN
       DO I = 1,6
        EDRTIME(I) = EERTIME(I)
       END DO
      ELSE IF (TFLAG.EQ.'SCET') THEN
       DO I = 1,6
        EDRTIME(I) = SCETIME(I)
       END DO
      END IF
C
      RETURN
      END
******************************************************************
C
C ROUTINE TO EXTRACT N BITS FROM ARRAY DATA STARTING AT BIT POSITION IOFF
C AND PLACE THESE BITS INTO WORD VAL STARTING AT BIT POSITION IBEG.
C
      SUBROUTINE MOVBIT(DATA,POS,NBITS,VAL,IBEG)
C
C DATA  INPUT DATA ARRAY
C POS   STARTING BIT POSISTION WITHIN ARRAY DATA (0 = FIRST BIT)
C NBITS NUMBER OF BITS TO BE MOVED
C VAL   OUTPUT WORD
C IBEG  STARTING BIT FOR INSERTION OF COPIED BITS
C
      INTEGER*4 VAL
      INTEGER*4 DATA(1),POS
      LOGICAL*4 IVAL
C
      IWORD = INT(POS/32) + 1
      IOFF = MOD(POS,32)
      DO I=0,NBITS-1
       IVAL = BTEST(DATA(IWORD),IOFF+I)
       IF (IVAL) VAL = (IBSET(VAL,IBEG+I))
       IF (.NOT.IVAL) VAL = (IBCLR(VAL,IBEG+I))
      END DO
C
      RETURN
      END
      INTEGER FUNCTION MODE(ISTAT)
C
C THIS FUNCTION IDENTIFIES THE APPROPRIATE TELEMETRY MODE FOR PROCESSING
C
C  CR-1 = 1
C  CR-2 = 2
C  CR-3 = 3
C  CR-4 = 4
C  CR-5 = 5
C  CR-6 = 6
C  CR-7 = 9
C  GS = 0
C  ENG = 8
C  VIM-5 = 13
C  N/A = -1
C
      INCLUDE 'UNPACK.INC'
C
      ISTAT = 0
C
      IF (DATMOD.EQ.0) MODE = 8
      IF (DATMOD.EQ.1) MODE = 2
      IF (DATMOD.EQ.2) MODE = 3
      IF (DATMOD.EQ.3) MODE = 4
      IF (DATMOD.EQ.4) MODE = 5
      IF (DATMOD.EQ.5) MODE = 6
      IF (DATMOD.EQ.6) MODE = 9
      IF (DATMOD.EQ.7) MODE = 1
      IF (DATMOD.EQ.8) MODE = -1
      IF (DATMOD.EQ.9) MODE = -1
      IF (DATMOD.EQ.10) MODE = 0
      IF (DATMOD.EQ.11) MODE = -1
      IF (DATMOD.EQ.12) MODE = 0
      IF (DATMOD.EQ.13) MODE = -1
      IF (DATMOD.EQ.14) MODE = 0
      IF (DATMOD.EQ.15) MODE = 0
      IF (DATMOD.EQ.16) MODE = -1
      IF (DATMOD.EQ.17) MODE = -1
      IF (DATMOD.EQ.18) MODE = -1
      IF (DATMOD.EQ.19) MODE = -1
      IF (DATMOD.EQ.20) MODE = -1
      IF (DATMOD.EQ.21) MODE = -1
      IF (DATMOD.EQ.22) MODE = 0
      IF (DATMOD.EQ.23) MODE = 0
      IF (DATMOD.EQ.24) MODE = 13
      IF (DATMOD.EQ.25) MODE = -1
      IF (DATMOD.EQ.26) MODE = 0
      IF (DATMOD.EQ.27) MODE = -1
      IF (DATMOD.EQ.28) MODE = -1
      IF (DATMOD.EQ.29) MODE = 13
      IF (DATMOD.EQ.30) MODE = -1
      IF (DATMOD.EQ.31) MODE = -1
C
      IF (DATMOD.LT.0.OR.DATMOD.GT.31) THEN
       WRITE(6,*)
       WRITE(6,*) '***INVALID DATMOD VALUE***'
       ISTAT = 1
       MODE = -1
      END IF
C
C     WRITE(6,*) 'DATMOD,MODE ',DATMOD,MODE
C
      RETURN
      END
      REAL*8 FUNCTION REALTIME(TIME)
C
C CONVERT INTEGER CALENDAR TIME INTO DECIMAL YEAR REAL TIME.
C
      INTEGER*2 TIME(6)
      REAL*8 DAYS
C
      DAYS = 365.0D0
      IF (MOD(TIME(1),4).EQ.0) DAYS = 366.0D0
      REALTIME = DBLE(TIME(1)) +
     &           DBLE(TIME(2)-1)/DAYS +
     &           DBLE(TIME(3))/24.0D0/DAYS +
     &           DBLE(TIME(4))/60.0D0/24.0D0/DAYS +
     &           DBLE(TIME(5))/60.0D0/60.0D0/24.0D0/DAYS +
     &           DBLE(TIME(6))/1000.0D0/60.0D0/60.0D0/24.0D0/DAYS
C
C ASSUME 2 DIGIT YEAR.  ANY YEAR BEFORE VOYAGER LAUNCH (77) IS INTO NEXT
C CENTURY.
C
      IF (TIME(1).LT.77) REALTIME = REALTIME + 100.0D0
C
      RETURN
      END

