if the value of date(1) sent to this subroutine is 0, then
the calendar date in a format is returned in date(1-2).
if the value of date(1) sent to this subroutine is not 0,
then the date array is not altered.
in the following, i=1 denotes real time and i=2 denotes
task time elapsed since timers were last read and set.
itot(i)= binary integer number of hundreths of seconds elapsed.
ihr(i) = hours elapsed.
imin(i)= minutes elapsed.
sec(i) = seconds elapsed.

dat0  = packed date for previous reading and setting.
dat1  = packed date for this reading and setting.
ireal0= real time (binary integer hundreths of seconds) for
previous reading and setting.
ireal1= real time (binary integer hundreths of seconds) for
this reading and setting.
itask = increment of task interval timer counted from when TIMDAT was
previously called (units of centiseconds).
itotsk= total task time elapsed from start of program run in
binary integer number of hundreths of seconds.
idayr = day of year in a format (only calculated if date(1)
has value 0 when sent to subroutine timdat).