CHARACTER*128 FUNCTION DBATLB(S1,S2)
      CHARACTER*26 S1
      CHARACTER*128 S2
      CHARACTER*4 TLB,TLBLC
      CHARACTER*1 BL
      DATA TLB/'.TLB'/, TLBLC/'.tlb'/, BL/' '/
C
      L1 = INDEX(S1,BL) - 1
      IF (L1 .EQ. -1)  L1 = 26
C      L2 = INDEX(S2,BL) - 1
      CALL DBLEN(S2,L2)
      IF (L1.GT.0) GOTO 4
        DBATLB = S2(:L2)
        GOTO 5
    4 DBATLB = S1(:L1)//S2(:L2)
    5 IF (L2 .LT. 4) GOTO 6
      L20 = L2 - 3
      IF (INDEX(S2(L20:L2),TLB  ) .EQ. 1) GOTO 10
      IF (INDEX(S2(L20:L2),TLBLC) .EQ. 1) GOTO 10
    6 LT1 = L1+L2+1
      LT4 = LT1+3
      DBATLB(LT1:LT4) = TLB
   10 RETURN
      END