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Re: [PATCH] softfloat: Fix BAD_SHIFT from normalizeFloatx80Subnormal
From: |
Alex Bennée |
Subject: |
Re: [PATCH] softfloat: Fix BAD_SHIFT from normalizeFloatx80Subnormal |
Date: |
Mon, 30 Mar 2020 12:32:24 +0100 |
User-agent: |
mu4e 1.3.10; emacs 28.0.50 |
Richard Henderson <address@hidden> writes:
> All other calls to normalize*Subnormal detect zero input before
> the call -- this is the only outlier. This case can happen with
> +0.0 + +0.0 = +0.0 or -0.0 + -0.0 = -0.0, so return a zero of
> the correct sign.
>
> Reported-by: Coverity (CID 1421991)
> Signed-off-by: Richard Henderson <address@hidden>
Queued to for-5.0/random-fixes, thanks.
> ---
> fpu/softfloat.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index 301ce3b537..ae6ba71854 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -5856,6 +5856,9 @@ static floatx80 addFloatx80Sigs(floatx80 a, floatx80 b,
> flag zSign,
> zSig1 = 0;
> zSig0 = aSig + bSig;
> if ( aExp == 0 ) {
> + if (zSig0 == 0) {
> + return packFloatx80(zSign, 0, 0);
> + }
> normalizeFloatx80Subnormal( zSig0, &zExp, &zSig0 );
> goto roundAndPack;
> }
--
Alex Bennée