[libre-riscv-dev] LibreSOC - RISCV and POWER dual architecture feasibility

[Luke Kenneth Casson Leighton]

On Sun, Mar 15, 2020 at 7:59 AM Jacob Lifshay <programmerjake at gmail.com> wrote:
>
> On Sat, Mar 14, 2020, 21:01 Luke Kenneth Casson Leighton <lkcl at lkcl.net>
> wrote:
>
> > 3) where is the port of softfloat-3 that supports POWER IEEE754 format?
> >
>
> You can use simple-soft-float which is (modulo possible bugs) entirely
> correct for Power except that it might propagate NaN payloads incorrectly
> since NaN payload propagation is only partially implemented and that it
> needs to have the additional 20-30 lines of trivial code added to record
> the cause for generating a NaN (because Power has more than the standard
> list of FP exception conditions).

yes.  could you add that?  it's important.  if you need a POWERPC
64-bit system to log in to in order to check that they're correct (by
doing "real" FP on a "real" POWER9 system) i can ask around.

l.