SUBROUTINE INXCB (I,IR,IDX,IDP)
C
C B(IDX) IS THE LOCATION OF THE FIRST ROOT OF THE B(I,IR) POLYNOMIAL
C
      COMMON /CCBLK/  NPP        ,K          ,EPS        ,CNV        ,
     1                NM         ,NCMPLX     ,IK
      IDP = 0
      IF (IR) 107,101,103
  101 IF (I-NM) 102,102,107
  102 IDX = I
      IDP = 1
      RETURN
  103 IZH = 2**IR
      ID = I-IZH-IZH
      IDX = ID+ID+(IR-1)*IK+IR+(IK-I)/IZH+4
      IPL = IZH-1
      IDP = IZH+IZH-1
      IF (I-IPL-NM) 105,105,104
  104 IDP = 0
      RETURN
  105 IF (I+IPL-NM) 107,107,106
  106 IDP = NM+IPL-I+1
  107 RETURN
      END

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