subroutine entsrc(irold,irnew)
c
c  this routine returns irold = lrecov and sets lrecov = irnew.
c
c  if there is an active error state, the message is printed
c  and execution stops.
c
c  irnew = 0 leaves lrecov unchanged, while
c  irnew = 1 gives recovery and
c  irnew = 2 turns recovery off.
c
c  error states -
c
c    1 - illegal value of irnew.
c    2 - called while in an error state.
c
      external i8save
c
      if (irnew.lt.0 .or. irnew.gt.2)
     1   call seterr(31hentsrc - illegal value of irnew,31,1,2)
c
      irold=i8save(2,irnew,irnew.ne.0)
c
c  if have an error state, stop execution.
c
      if (i8save(1,0,.false.) .ne. 0) call seterr
     1   (39hentsrc - called while in an error state,39,2,2)
c
      return
c
      end