Re: [musl] ld128 math function support

[Szabolcs Nagy <nsz@port70.net>]

* gzh2233 <gzh1754344759@163.com> [2022-12-08 15:56:35 +0800]:
> I am trying to use ld128 in x86_64 musl and i have some problems.

that has multiple issues.

> Long double format is defined in arch/x86_64/bits/float.h and i am trying to
> change long double relevant macros. However, many long double functions
> still use double implementions(mostly "xxhl" functions). This is just a way to
> make musl compile and can be a problem in some cases. Simply changing
> the long double relevant macros can change ld80 into ld128 but this
> problem still exists. 
> 
> 
> Is there any official support for long double math functions?

musl does not support long double == float128 on x86_64.
this is part of the abi.

if you add a new abi variant where long double is float128,
that works but many float128 math functions have low quality
currently as you noticed. fixing this is significant effort.
i don't have immediate plans to fix this.

another option is to keep long double as is but add _Float128
support and f128 math functions (on all targets). such support
would require additional work and increase the size of libc.so.