gcc5 caused an unexpected error for 128 bit floating point numbers

[Andreas Tobler]

On 20.12.15 11:16, Jukka Ukkonen wrote:
>
> Hello all,
>
> I installed gcc5 from ports (gcc5-5.3.0) expecting it to be
> able to handle 128 bit floating point numbers on ppc64.
> It turns out, this does not work quite right. Apparently gcc5
> tries to compile any basic 128 bit floating point operations
> to calls to functions like __gcc_qmul, _gcc_qdiv, etc.
> If such function wrappers are used at all, I guess they should
> be implemented as inline assebler wrappers or something instead
> of genuine functions, right?

The support for soft float128 is not implemented yet. I excluded the 
functionality at the time I did the port. I'll revisit.
Real float128 support requires a VSX capable cpu, power7+ and up. And 
this is work in progress on the gcc side. In theory it might be possible 
to tweak altivec to achive the same but this is not on my top list until 
reality has settled down, iow until real float128 has entered gcc land 
and this will happen earliest with gcc-7.

Andreas