*IF DEF,C94_1A,OR,DEF,UTILIO,OR,DEF,FLDIO,OR,DEF,C98_1A,OR,DEF,RECON       UIE3F404.49     
C ******************************COPYRIGHT******************************    GTS2F400.7129   
C (c) CROWN COPYRIGHT 1995, METEOROLOGICAL OFFICE, All Rights Reserved.    GTS2F400.7130   
C                                                                          GTS2F400.7131   
C Use, duplication or disclosure of this code is subject to the            GTS2F400.7132   
C restrictions as set forth in the contract.                               GTS2F400.7133   
C                                                                          GTS2F400.7134   
C                Meteorological Office                                     GTS2F400.7135   
C                London Road                                               GTS2F400.7136   
C                BRACKNELL                                                 GTS2F400.7137   
C                Berkshire UK                                              GTS2F400.7138   
C                RG12 2SZ                                                  GTS2F400.7139   
C                                                                          GTS2F400.7140   
C If no contract has been raised with this copy of the code, the use,      GTS2F400.7141   
C duplication or disclosure of it is strictly prohibited.  Permission      GTS2F400.7142   
C to do so must first be obtained in writing from the Head of Numerical    GTS2F400.7143   
C Modelling at the above address.                                          GTS2F400.7144   
C ******************************COPYRIGHT******************************    GTS2F400.7145   
C                                                                          GTS2F400.7146   
CLL  Function:  P21BITS ------------------------------------------------   P21BIT1A.3      
CLL                                                                        P21BIT1A.4      
CLL  Purpose: Returns the number of bits used for exponent in packing      P21BIT1A.5      
CLL           and unpacking Cray 64 bit words to/from 32 bit words by      P21BIT1A.6      
CLL           Cray routines PACK21 and EXPAND21.  As from vn2.6 this       P21BIT1A.7      
CLL           becomes a function of dump/PP/ancillary file format          P21BIT1A.8      
CLL           version number.                                              P21BIT1A.9      
CLL           For the present P21BITS=6 whatever version number.           P21BIT1A.10     
CLL           This may be reconsidered in future.                          P21BIT1A.11     
CLL                                                                        P21BIT1A.12     
CLL  Author:   T.Johns            Date:           08 May 1992              P21BIT1A.13     
CLL                                                                        P21BIT1A.14     
CLL  Tested under compiler:   cf77                                         P21BIT1A.15     
CLL  Tested under OS version: UNICOS 6.1.5a                                P21BIT1A.16     
CLL                                                                        P21BIT1A.17     
CLL  Model            Modification history from model version 3.0:         P21BIT1A.18     
CLL version  date                                                          P21BIT1A.19     
CLL                                                                        P21BIT1A.20     
CLL                                                                        P21BIT1A.21     
CLL  Programming standard: UM Doc Paper 3, version 2 (7/9/90)              P21BIT1A.22     
CLL                                                                        P21BIT1A.23     
CLL  Logical components covered: S4                                        P21BIT1A.24     
CLL                                                                        P21BIT1A.25     
CLL  Project task: S420                                                    P21BIT1A.26     
CLL                                                                        P21BIT1A.27     
CLL  External documentation:                                               P21BIT1A.28     
CLL    UMDP F3                                                             P21BIT1A.29     
CLL                                                                        P21BIT1A.30     
C*L  Interface and arguments: ------------------------------------------   P21BIT1A.31     
C                                                                          P21BIT1A.32     

      INTEGER FUNCTION P21BITS(version)                                     16P21BIT1A.33     
C                                                                          P21BIT1A.34     
      IMPLICIT NONE                                                        P21BIT1A.35     
C                                                                          P21BIT1A.36     
      INTEGER                                                              P21BIT1A.37     
     &    version  ! IN  UM dump/pp/ancillary file format version          P21BIT1A.38     
C                                                                          P21BIT1A.39     
C* ---------------------------------------------------------------------   P21BIT1A.40     
C                                                                          P21BIT1A.41     
      P21BITS=6                                                            P21BIT1A.42     
C                                                                          P21BIT1A.43     
      RETURN                                                               P21BIT1A.44     
      END                                                                  P21BIT1A.45     
*ENDIF                                                                     P21BIT1A.46