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Re: [Qemu-devel] [PATCH] fpu/softfloat.c: Return correctly signed values
From: |
Aurelien Jarno |
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 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, Sep 28, 2012 at 04:42:16PM +0100, Peter Maydell wrote:
> On 28 September 2012 16:17, Peter Maydell <address@hidden> 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 <address@hidden>
> > ---
> > 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
address@hidden http://www.aurel32.net