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References: <20181124235553.17371-1-cota@braap.org>
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From: Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>
In-reply-to: <e39db85e-52b5-bdc8-d9a7-e3a14f78ce4b@linaro.org>
Date: Tue, 04 Dec 2018 13:52:16 +0000
Message-ID: <87ftvd2ycv.fsf@linaro.org>
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Subject: Re: [Qemu-devel] [PATCH v6 07/13] fpu: introduce hardfloat
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To: Richard Henderson <richard.henderson@linaro.org>
Cc: "Emilio G. Cota" <cota@braap.org>, qemu-devel@nongnu.org


Richard Henderson <richard.henderson@linaro.org> writes:

> On 12/4/18 6:28 AM, Alex Benn=C3=A9e wrote:
>> Emilio G. Cota <cota@braap.org> writes:
>>> This assumes that QEMU is running on an IEEE754-compliant FPU and
>>> that the rounding is set to the default (to nearest). The
>>> implementation-dependent specifics of the FPU should not matter; things
>>> like tininess detection and snan representation are still dealt with in
>>> soft-fp. However, this approach will break on most hosts if we compile
>>> QEMU with flags such as -ffast-math. We control the flags so this should
>>> be easy to enforce though.
>>
>> We don't currently enforce this though although maybe that would be too
>> much hand holding for compiler ricers hell bent on not understanding the
>> flags they use.
>
> We could always
>
> #ifdef __FAST_MATH__
> #error "Silliness like this will get you nowhere"
> #endif

Emilio, are you happy to add that guard with a suitable pithy comment?

--
Alex Benn=C3=A9e