*
* $Id: epupdh.F,v 1.1.1.1 1996/03/08 15:21:44 mclareni Exp $
*
* $Log: epupdh.F,v $
* Revision 1.1.1.1  1996/03/08 15:21:44  mclareni
* Epio
*
*
#include "epio/pilot.h"
      SUBROUTINE EPUPDH(LUNIT,NH,IH,IBUF,IERR)
C.
C. UPDATES THE (OPTIONAL) USER PORTION OF THE PHYSICAL
C. BLOCK HEADER.
C. THE NECESSARY SPACE FOR THIS OPTIONAL PORTION MUST HAVE
C. BEEN RESERVED BY THE USER THROUGH A FOREGOING CALL
C. TO EPADDH (TYPICALLY ONCE AT THE START OF THE JOB).
C. WHEREAS A CALL TO EPADDH CAUSES THE EXISTING (IF
C. ANY) BLOCK TO BE WRITTEN OUT, EPUPDH DOES NOT HAVE THIS
C. EFFECT.
C.
C. INPUT:
C
C. LUNIT   LOGICAL UNIT
C.
C. NH      NO. OF USER WORDS IN HEADER TO BE UPDATED.
C.         NH IS CUT AT THE ACTUAL NO. OF EXTRA USER WORDS
C.         AVAILABLE IN THE PHYSICAL BLOCK HEADER.
C.
C. IH      ARRAY CONTAINING THE NEW VALUES.
C.         WORDS 1..NH OF IH WILL REPLACE THE CURRENT WORDS
C.         1..NH OF THE USER PORTION IN THE HEADER.
C.         Important: if in 32 p.h. mode, user words must be converted
C.         to IBM format (integer or floating) by the user beforehand
C.
C. IBUF    UNIT BUFFER
C.
C. IERR    ERROR CONDITION - SEE SEPERATE LIST
C.
#include "epio/epiocom.inc"
      DIMENSION IH(2),IBUF(2)
C--- CHECK WHETHER SAME USER UNIT AS LAST TIME
      IF(LASTUT.EQ.LUNIT)  GOTO 1551
C--- NEW UNIT - GET REF
      CALL EPUNIT(LUNIT,IERR)
      IF(IERR.EQ.0)  GOTO 1552
      GOTO 77777
 1551 IERR=0
      IF(LREF.NE.0)  GOTO 1552
      IERR=13
      CALL EPERRH(LUNIT,IERR)
      GOTO 77777
 1552 CONTINUE
C--- IGNORE IF NO OUTPUT UNIT, OR UNIT NOT YET USED
      IF(LIST(ISTART+16).EQ.2.OR.LIST(ISTART+14).EQ.0)  GOTO 77777
      IF(LIST(ISTART+29).EQ.0)  THEN
*--- 16 bit p.h.
         K=MIN(LIST(ISTART+7)-LIST(6),NH)
         CALL BUN16W(IH,1,IBUF,LIST(6)+1,K)
      ELSE
         K=MIN(LIST(ISTART+7)/2-LIST(6),NH)
         CALL BUN32W(IH,1,IBUF,LIST(6)+1,K)
      ENDIF
77777 RETURN
      END