* [PATCH] softfloat: Fix BAD_SHIFT from normalizeFloatx80Subnormal
@ 2020-03-27 23:20 Richard Henderson
2020-03-30 11:32 ` Alex Bennée
0 siblings, 1 reply; 2+ messages in thread
From: Richard Henderson @ 2020-03-27 23:20 UTC (permalink / raw)
To: qemu-devel; +Cc: peter.maydell, alex.bennee
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 <richard.henderson@linaro.org>
---
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;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] softfloat: Fix BAD_SHIFT from normalizeFloatx80Subnormal
2020-03-27 23:20 [PATCH] softfloat: Fix BAD_SHIFT from normalizeFloatx80Subnormal Richard Henderson
@ 2020-03-30 11:32 ` Alex Bennée
0 siblings, 0 replies; 2+ messages in thread
From: Alex Bennée @ 2020-03-30 11:32 UTC (permalink / raw)
To: Richard Henderson; +Cc: peter.maydell, qemu-devel
Richard Henderson <richard.henderson@linaro.org> 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 <richard.henderson@linaro.org>
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
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2020-03-27 23:20 [PATCH] softfloat: Fix BAD_SHIFT from normalizeFloatx80Subnormal Richard Henderson
2020-03-30 11:32 ` Alex Bennée
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