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Re: RISC-V glibc port, v7
On Mon, Jan 29, 2018 at 12:30 PM, Joseph Myers <joseph@codesourcery.com> wrote:
> On Mon, 29 Jan 2018, Andrew Waterman wrote:
>
>> My reading of Annex F is that either the old or new semantics for
>> these instructions suffices to implement the C functions, since the
>> standard generally leaves signaling-NaN behavior implementation
>> defined.
>
> Annex F does not define signaling NaN semantics. TS 18661-1:2014 does,
> and is what we follow in glibc. (For example, AArch64 has instructions
> with exactly the semantics required to implement fmax and fmin with single
> instructions.)
>
> The proposed revision for binding to IEEE 754-2018 keeps fmax and fmin as
> in TS 18661-1:2014 (but no longer with an IEEE operation to bind to),
> removes fmaxmag and fminmag, and adds new functions fmaximum, fminimum,
> fmaximum_mag, fminimum_mag, fmaximum_num, fminimum_num, fmaximum_mag_num
> and fminimum_mag_num (along with type-generic macros for them, and
> likewise for other floating-point types).
Thanks for the info.
>
> --
> Joseph S. Myers
> joseph@codesourcery.com