  We present an extended scheme for the calculation of the profiles of emission
lines from accretion discs around rotating black holes. The scheme includes
discs with angular momenta which are parallel and antiparallel with respect to
the black hole's angular momentum, as both configurations are assumed to be
stable (King et al., 2005). We discuss line shapes for such discs and present a
code for modelling observational data with this scheme in X-ray data analysis
programs. Based on a Green's function approach, an arbitrary radius dependence
of the disc emissivity and arbitrary limb darkening laws can be easily taken
into account, while the amount of precomputed data is significantly reduced
with respect to other available models.
