|
From: | Aleksandar Markovic |
Subject: | Re: [PATCH v1 5/7] fpu/softfloat: avoid undefined behaviour when normalising empty sigs |
Date: | Fri, 27 Mar 2020 12:13:48 +0200 |
11:53 Pet, 27.03.2020. Alex Bennée <address@hidden> је написао/ла:
>
> The undefined behaviour checker
Alex, what exactly is "undefined behaviour checker"? If this is a test, can you give us a link?
Sincerely,
Aleksandar
> pointed out that a shift of 64 would
> lead to undefined behaviour.
>
> Signed-off-by: Alex Bennée <address@hidden>
> ---
> fpu/softfloat.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index 301ce3b537b..444d35920dd 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -3834,9 +3834,14 @@ void normalizeFloatx80Subnormal(uint64_t aSig, int32_t *zExpPtr,
> {
> int8_t shiftCount;
>
> - shiftCount = clz64(aSig);
> - *zSigPtr = aSig<<shiftCount;
> - *zExpPtr = 1 - shiftCount;
> + if (aSig) {
> + shiftCount = clz64(aSig);
> + *zSigPtr = aSig << shiftCount;
> + *zExpPtr = 1 - shiftCount;
> + } else {
> + *zSigPtr = 0;
> + *zExpPtr = 1 - 64;
> + }
> }
>
> /*----------------------------------------------------------------------------
> --
> 2.20.1
>
>
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