  SwiftJ0243.6+6124, the first Galactic ultra-luminous X-ray pulsar, was
observed during its 2017-2018 outburst with \emph{AstroSat} at both sub- and
super-Eddington levels of accretionwith X-ray luminosities of
$L_{X}{\sim}7{\times}10^{37}$ and $6{\times}10^{38}$$ergs^{-1}$,
respectively.Our broadband timing and spectral observations show that X-ray
pulsations at ${\sim}9.85\rm{s}$ have been detected up to 150keV when the
source was accreting at the super-Eddington level.The pulse profiles are a
strong function of both energy and source luminosity,showing a double-peaked
profile with pulse fraction increasing from $\sim$$10{\%}$ at $1.65\rm{keV}$ to
40--80$\%$ at $70\rm{keV}$.The continuum X-ray spectra are well-modeled with a
high energy cut-off power law($\Gamma$${\sim}$0.6-0.7) and one or two blackbody
components with temperatures of $\sim$0.35$\rm{keV}$ and $1.2\rm{keV}$,
depending on the accretion level.No iron line emission is observed at
sub-Eddington level, while a broad emission feature at around 6.9keV is
observed at the super-Eddington level, along with a blackbody
radius($121-142\rm{km}$) that indicates the presence of optically thick
outflows.
