Re: [PATCH v4 1/2] softfloat: add APIs to handle alternative sNaN propagation for fmax/fmin

[Richard Henderson]

On 10/16/21 1:54 AM, frank.chang@sifive.com wrote:
> From: Chih-Min Chao<chihmin.chao@sifive.com>
>
> For "fmax/fmin ft0, ft1, ft2" and if one of the inputs is sNaN,
>
>    The original logic:
>      Return NaN and set invalid flag if ft1 == sNaN || ft2 == sNan.
>
>    The alternative path:
>      Set invalid flag if ft1 == sNaN || ft2 == sNaN.
>      Return NaN only if ft1 == NaN && ft2 == NaN.
>
> The IEEE 754 spec allows both implementation and some architecture such
> as riscv choose different defintions in two spec versions.
> (riscv-spec-v2.2 use original version, riscv-spec-20191213 changes to
>   alternative)
>
> Signed-off-by: Chih-Min Chao<chihmin.chao@sifive.com>
> Signed-off-by: Frank Chang<frank.chang@sifive.com>
> ---
>   fpu/softfloat-parts.c.inc | 25 +++++++++++++++++++++++--
>   fpu/softfloat.c           | 19 +++++++++++++------
>   include/fpu/softfloat.h   | 10 ++++++++++
>   3 files changed, 46 insertions(+), 8 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~