ADAS Subroutine xxr8sort

      SUBROUTINE XXR8SORT(N, LUP, XA, IA)                                         

C-----------------------------------------------------------------------
C
C  ****************** FORTRAN77 SUBROUTINE: XXR8SORT *******************
C
C  PURPOSE: Sorts a REAL*8 array xa and its index array. This is a
C           bubble sort designed for small arrays.         
C                                                                    
C
C  CALLING PROGRAM:  General use
C
C                                                                   
C  SUBROUTINE:
C
C  INPUT       :  (I*4)  N   = Size of input arrays
C  INPUT       :  (L*4)  LUP = .TRUE. sort in ascending order
C                              .FALSE. descending order
C  INPUT/OUPUT :  (R*8)  XA  = Array to be sorted
C  INPUT/OUPUT :  (I*4)  IA  = Original index of sorted XA
C 
C  ROUTINES: NONE
C
C  NOTES: Based on nsort
C
C  AUTHOR:  Martin O'Mullane
C           K1/1/52
C
C  DATE:    19/07/99
C
C  VERSION: 1.1
C  
C
C-----------------------------------------------------------------------

C-----------------------------------------------------------------------
      INTEGER             IA(*),       N
      LOGICAL             LUP
      REAL*8              XA(*)