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Sender: Richard Henderson <rth7680@gmail.com>
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Date: Mon, 06 Jan 2014 10:18:41 -0800
From: Richard Henderson <rth@twiddle.net>
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Subject: Re: [Qemu-devel] [PATCH v2 01/24] softfloat: Fix exception flag
	handling for float32_to_float16()
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To: Peter Maydell <peter.maydell@linaro.org>, qemu-devel@nongnu.org
Cc: Tom Musta <tommusta@gmail.com>, Peter Crosthwaite <peter.crosthwaite@xilinx.com>, patches@linaro.org, Michael Matz <matz@suse.de>, Alexander Graf <agraf@suse.de>, Claudio Fontana <claudio.fontana@linaro.org>, Dirk Mueller <dmueller@suse.de>, Will Newton <will.newton@linaro.org>, Laurent Desnogues <laurent.desnogues@gmail.com>, =?ISO-8859-1?Q?Alex_Benn=E9e?= <alex.bennee@linaro.org>, kvmarm@lists.cs.columbia.edu, Christoffer Dall <christoffer.dall@linaro.org>

On 01/06/2014 05:10 AM, Peter Maydell wrote:
> Our float32 to float16 conversion routine was generating the correct
> numerical answers, but not always setting the right set of exception
> flags. Fix this, mostly by rearranging the code to more closely
> resemble RoundAndPackFloat*, and in particular:
>  * non-IEEE halfprec always raises Invalid for input NaNs
>  * we need to check for the overflow case before underflow
>  * we weren't getting the tininess-detected-after-rounding
>    case correct (somewhat academic since only ARM uses halfprec
>    and it is always tininess-detected-before-rounding)
>  * non-IEEE halfprec overflow raises only Invalid, not
>    Invalid + Inexact
>  * we weren't setting Inexact when we should
> 
> Also add some clarifying comments about what the code is doing.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  fpu/softfloat.c | 105 +++++++++++++++++++++++++++++++++++---------------------
>  1 file changed, 66 insertions(+), 39 deletions(-)

Reviewed-by: Richard Henderson <rth@twiddle.net>


r~