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Date: Mon, 1 Oct 2012 18:59:10 +0200
From: Aurelien Jarno <aurelien@aurel32.net>
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Subject: Re: [Qemu-devel] [PATCH] fpu/softfloat.c: Return correctly signed
 values from uint64_to_float32
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Alexander Graf <agraf@suse.de>, Richard Henderson <rth@twiddle.net>, qemu-devel@nongnu.org, patches@linaro.org

On Fri, Sep 28, 2012 at 04:42:16PM +0100, Peter Maydell wrote:
> On 28 September 2012 16:17, Peter Maydell <peter.maydell@linaro.org> wrote:
> > The uint64_to_float32() conversion function was incorrectly always
> > returning numbers with the sign bit set (ie negative numbers). Correct
> > this so we return positive numbers instead.
> >
> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> > ---
> > As far as I can see we use this function only in the three PPC SPE
> > insns efscfuf, efsctsf, efsctuf. It is therefore untested(!); if
> > anybody with PPC hw to test against could check the results of
> > those functions that would be cool.

SPE instructions are not common on the non-embedded world, as far as I
know it should be tested using the e500 CPU. That said I don't have a
kernel nor an image for such a machine. 

> ...incidentally in two of those uses we're operating on a constant:
>  tmp = uint64_to_float64(1ULL << 32, &env->vec_status);
> and it would probably be better to use make_float64() instead.
> 

Agreed.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net