[PATCH 1/1] RISC-V: Use the new libm code if possible

[Kito Cheng]

LGTM, thank Hau :)


On Wed, Feb 22, 2023 at 9:59 AM Hau Hsu <hau.hsu@sifive.com> wrote:
>
> Set  __OBSOLETE_MATH_DEFAULT to 0 if 'd' extension is supported (i.e.
> __riscv_flen == 64).
>
> Base on the comment for  __OBSOLETE_MATH_DEFAULT:
>
> > ... it assumes that the toolchain has ISO C99 support (hexfloat
> > literals, standard fenv semantics), the target has IEEE-754 conforming
> > binary32 float and binary64 double (not mixed endian) representation,
> > standard SNaN representation, double and single precision arithmetics
> > has similar latency and it has no legacy SVID matherr support, only
> > POSIX errno and fenv exception based error handling.
>
> Signed-off-by: Hau Hsu <hau.hsu@sifive.com>
> ---
>  newlib/libc/include/machine/ieeefp.h | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/newlib/libc/include/machine/ieeefp.h b/newlib/libc/include/machine/ieeefp.h
> index 9bb8af02f..a29557a6d 100644
> --- a/newlib/libc/include/machine/ieeefp.h
> +++ b/newlib/libc/include/machine/ieeefp.h
> @@ -221,6 +221,11 @@
>  #ifdef __riscv_flen
>  # define _SUPPORTS_ERREXCEPT
>  #endif
> +#if __riscv_flen == 64
> +# define __OBSOLETE_MATH_DEFAULT 0
> +#else
> +# define __OBSOLETE_MATH_DEFAULT 1
> +#endif
>  #endif
>
>  #ifdef __i960__
> --
> 2.39.0
>