pkb8.f

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C> @file
C> @brief Encode an 8-byte integer value within an integer array.
C>
C> @author J. Woollen @date 2022-05-06
 
C> This subroutine encodes an 8-byte integer value within a specified
C> number of bits of an integer array, starting at the bit
C> immediately after a specified bit within the array.
C>
C> This subroutine will not work properly if NBITS is less than 0 or
C> greater than 64, as determined via an internal call to subroutine
C> wrdlen().
C>      
C> This subroutine is the logical inverse of subroutine up8().
C>
C> @param[in] NVAL - integer*8: Value to be encoded.
C> @param[in] NBITS - integer: Number of bits of IBAY within
C> which to encode NVAL. Must be between 0 and 64.
C> @param[out] IBAY - integer(*): Array containing encoded NVAL.
C> @param[in,out] IBIT - integer: Bit pointer within IBAY
C> - On input, IBIT points to the bit within
C>   IBAY after which to begin encoding NVAL.
C> - On output, IBIT points to the last bit
C>   of IBAY which contains the encoded NVAL.
C>
C> @author J. Woollen @date 2022-05-06
      subroutine pkb8(nval,nbits,ibay,ibit)
 
      common /hrdwrd/ nbytw,nbitw,iord(8)
 
      integer(8) :: nval
      integer(4) :: nbits,ibit,ibay(*)
 
      integer(8) :: nval8
      integer(4) :: nval4
      integer(4) :: nvals(2)
 
      equivalence(nval8,nvals)
 
!----------------------------------------------------------------------
!----------------------------------------------------------------------
 
      if(nbits<0 ) call bort('bufrlib: pkb8 - nbits < zero !!!!!')
      if(nbits>64) call bort('bufrlib: pkb8 - nbits > 64   !!!!!')
 
      nval8=nval
      nval4=nvals(2)
      call pkb(nval4,max(nbits-nbitw,0),ibay,ibit)
      nval4=nvals(1)
      call pkb(nval4,min(nbits,nbitw  ),ibay,ibit)
 
      end subroutine