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From: Aurelien Jarno <aurelien@aurel32.net>
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
Subject: Re: [Qemu-devel] [PATCH] fpu/softfloat.c: Return correctly signed values from uint64_to_float32
Date: Mon, 1 Oct 2012 18:59:10 +0200	[thread overview]
Message-ID: <20121001165910.GC4055@ohm.aurel32.net> (raw)
In-Reply-To: <CAFEAcA-N08iVD3e1hN6-W7d_m8b_yNMQY9U2auJV7Jspwif1bg@mail.gmail.com>

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

  reply	other threads:[~2012-10-01 16:59 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-28 15:17 [Qemu-devel] [PATCH] fpu/softfloat.c: Return correctly signed values from uint64_to_float32 Peter Maydell
2012-09-28 15:42 ` Peter Maydell
2012-10-01 16:59   ` Aurelien Jarno [this message]
2012-10-01 16:56 ` Aurelien Jarno
2012-10-01 20:12 ` Aurelien Jarno

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