call CAL_TOSECONDS( difftime, prevfldsecs, mythid )
prevfldsecs = int((prevfldsecs+0.5)/fldperiod)*fldperiod
prevfldcount = int((prevfldsecs+0.5)/fldperiod) + 1
_RL prevfldsecs
prevfldsecs = fldsecs - modelstep
prevfldsecs = 0
prevfldcount= int((prevfldsecs+0.5)/fldperiod) + 1
do while ( prevfldsecs .lt. 0 )
prevfldsecs = prevfldsecs + repeatPeriod
prevfldsecs = mod(prevfldsecs,repeatPeriod)
prevfldsecs = int(prevfldsecs/fldperiod)*fldperiod
prevfldcount = int(prevfldsecs/fldperiod) + 1