%ROUTINE scalereg(%INTEGER reg,scale)
!***********************************************************************
!*    Performs a simple shift optimising shifts by 0 & 1               *
!*    While were are working to the LARGE Unix model arrays            *
!*    are restricted to 64K bytes hence any index can not be larger    *
!*    than 16 bits after scaling and can use 16 bit instructions       *
!*    If we move to the HUGE model then this routine will have to      *
!*    do 32 shifts with only 16 bit instructions -- Repulsive          *
!***********************************************************************
      %IF scale<=0 %THEN %RETURN
      %IF scale=1 %THEN OpRRS(ADD,reg+1,reg+1) %ELSE OpLit(SHL,scale,reg+1)
%END
%END %OF %FILE