We should implement F and D extensions (floating-point instructions), and possibly also Zfhmin and Zfh - half-precision floating-point. These extensions require additional registers and the use of CSRs, which might be the most complex part of the implementation.

As a stepping stone towards F and D, there are extensions Zfinx, Zdinx, Zhinx, Zhinxmin for floating-point operations in integer registers.