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Subject: RE: [ping][patch] Fixed-point patch 2/10
Date: Mon, 06 Aug 2007 23:20:00 -0000
Message-ID: <3CB54817FDF733459B230DD27C690CEC03EE8F00@Exchange.mips.com>
In-Reply-To: <3CB54817FDF733459B230DD27C690CEC03EE8EFF@Exchange.mips.com>
From: "Fu, Chao-Ying" <fu@mips.com>
To: "Mark Mitchell" <mark@codesourcery.com>,         "Stephens, Nigel" <nigel@mips.com>
Cc: <gcc-patches@gcc.gnu.org>, "Thekkath, Radhika" <radhika@mips.com>
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>=20
> Mark Mitchell wrote:
> >=20
> > Nigel Stephens wrote:
> > >=20
> > >=20
> > > Mark Mitchell wrote:
> > >> Fu, Chao-Ying wrote:
> > >>
> > >>=20=20
> > >>> Ex 2: (A and B are negative. )
> > >>> A.high =3D 0xffffffffffffffff and A.low =3D 0x8000000000000000
> > >>> B.high =3D 0xffffffffffffffff and B.low =3D 0x0000000000000001
> > >>> =3D> A > B, because A.high =3D=3D B.high and
> > >>> (unsigned HOST_WIDE_INT) a.low > (unsigned HOST_WIDE_INT) b.low
> > >>>=20=20=20=20=20
> > >>
> > >> Yes, I see; two's complement is set up so that after=20
> > masking the sign
> > >> bit, you can do an unsigned compare.  Thank you for explaining.
> > >>=20=20=20
> > >=20
> > > Since double_int is already declared with low unsigned, like this:
> > >=20
> > >    typedef struct
> > >    {
> > >      unsigned HOST_WIDE_INT low;
> > >      HOST_WIDE_INT high;
> > >    } double_int;
> > >=20
> > >=20
> > > Would it be more obvious to simply remove the casts=20
> altogether, e.g.
> >=20
> > There's a comment in double-int.h that suggests that the=20
> signedness of
> > low/high is historical and subject to change.  So, I think=20
> > the casts are
> > OK -- but I think omitting them is also OK.  Chao-Ying, you=20
> may decide
> > that as you please.
> >=20
>=20=20
>   Ok. I will omit them.  Thanks!
>=20

  This patch (2/10) is applied.  Thanks a lot!

Regards,
Chao-ying