From: Chih-Min Chao <chihmin.chao@sifive.com>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: "Alex Bennée" <alex.bennee@linaro.org>,
"open list:RISC-V" <qemu-riscv@nongnu.org>,
"qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>,
"Aurelien Jarno" <aurelien@aurel32.net>,
"Peter Maydell" <peter.maydell@linaro.org>
Subject: Re: [PATCH 2/3] softfloat: add APIs to handle alternative sNaN propagation
Date: Fri, 14 Aug 2020 16:59:53 +0800 [thread overview]
Message-ID: <CAEiOBXXOj5TcseHqpCaB-vR=3wFquP2ScjKGSrPXombesyD1jg@mail.gmail.com> (raw)
In-Reply-To: <aa334be5-e325-8d96-a3ee-00c82cfe2c4d@linaro.org>
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On Fri, Aug 14, 2020 at 1:21 AM Richard Henderson <
richard.henderson@linaro.org> wrote:
> On 7/30/20 2:52 AM, Chih-Min Chao wrote:
> > 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 if ft1 == sNaN && ft2 == sNaN
> >
> > The ieee754 spec allows both implementation and some architecture such
> > as riscv choose differenct defintion 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>
>
> If both ft1 and ft2 are SNaN, surely the returned result is silenced?
> That is
> something that is handled by pick_nan, but is not handled here.
>
Yes, it returns the default_nan, qNaN.
>
> Also, the patch subject should be modified to emphasize that this only
> applies
> to min/max and not propagation of all SNaN.
>
> Will be fixed in the next version.
By the way, the other patches have been queued in softfloat-next.
Do I need to resend the other two patches in the next version or just this
one ?
Chih-Min Chao
>
>
> r~
>
>
>
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next prev parent reply other threads:[~2020-08-14 9:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 9:52 [PATCH 0/3] float16 APIs and alternative sNaN handling Chih-Min Chao
2020-07-30 9:52 ` [PATCH 1/3] softfloat: target/riscv: implement full set fp16 comparision Chih-Min Chao
2020-08-12 16:30 ` Alistair Francis
2020-08-13 17:22 ` Richard Henderson
2020-07-30 9:52 ` [PATCH 2/3] softfloat: add APIs to handle alternative sNaN propagation Chih-Min Chao
2020-08-13 17:21 ` Richard Henderson
2020-08-14 8:59 ` Chih-Min Chao [this message]
2020-08-14 16:15 ` Richard Henderson
2020-07-30 9:52 ` [PATCH 3/3] softfloat: add fp16 and uint8/int8 interconvert functions Chih-Min Chao
2020-08-13 17:25 ` Richard Henderson
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