decfp_mf.F

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      SUBROUTINE decfp_mf (PFVAL,KEXP,KMANT)
      USE parkind1, ONLY : jprb
      USE yomhook , ONLY : lhook, dr_hook
      USE lfi_precision
!
!********************************************************************
!*
!*    NAME      : DECFP
!*
!*    FUNCTION  : DECODE GRIB CODE REPRESENTATION TO
!*                FLOATING POINT NUMBER.
!*
!*    INPUT     : KEXP  - 8 BIT SIGNED EXPONENT
!*                KMANT - 24 BIT MANTISSA
!*
!*    OUTPUT    : PFVAL - FLOATING POINT NUMBER
!*                KEXP  - UNCHANGED
!*                KMANT - UNCHANGED
!*
!*    JOHN HENNESSY , ECMWF , 15TH APRIL 1985
!*
!*    Modified by Jean CLOCHARD, February 1990, to comply with "DOCTOR",
!*    and to get a more straight-forward code.
!*
!********************************************************************
!
      IMPLICIT NONE
!
      INTEGER (KIND=JPLIKM) :: KEXP
      INTEGER (KIND=JPLIKM) :: KMANT
!
      REAL (KIND=JPDBLD) :: PFVAL
!
      REAL (KIND=JPDBLD) :: ZC16
!
      SAVE zc16
      DATA zc16 / 16.0_jpdbld /
!
!      Direct decoding, depending on sign bit, included in KEXP.
!
!
      REAL(KIND=JPRB) :: ZHOOK_HANDLE
      IF (lhook) CALL dr_hook('DECFP_MF',0,zhook_handle)
      IF (kexp.LT.128) THEN
        pfval = kmant*(zc16**(kexp-70))
      ELSE
        pfval = -kmant*(zc16**(kexp-198))
      ENDIF
!
!
      IF (lhook) CALL dr_hook('DECFP_MF',1,zhook_handle)
      ENDSUBROUTINE decfp_mf