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Re: [PATCH 4/5] Use movq for 64-bit operations
- From: OndÅej BÃlka <neleai at seznam dot cz>
- To: Richard Henderson <rth at twiddle dot net>
- Cc: Peter Collingbourne <pcc at google dot com>, libc-alpha at sourceware dot org
- Date: Mon, 13 May 2013 18:45:21 +0200
- Subject: Re: [PATCH 4/5] Use movq for 64-bit operations
- References: <1368459372-2415-1-git-send-email-pcc at google dot com> <1368459372-2415-5-git-send-email-pcc at google dot com> <5191142C dot 7070101 at twiddle dot net>
On Mon, May 13, 2013 at 09:26:20AM -0700, Richard Henderson wrote:
> On 05/13/2013 08:36 AM, Peter Collingbourne wrote:
> > The EXTRACT_WORDS64 and INSERT_WORDS64 macros use movd for a 64-bit
> > operation. Somehow gcc manages to turn this into movq, but LLVM won't.
> >
> > 2013-05-13 Peter Collingbourne <pcc@google.com>
> >
> > * sysdeps/x86_64/fpu/math_private.h (MOVQ): New macro.
> > (EXTRACT_WORDS64) Use where appropriate.
> > (INSERT_WORDS64) Likewise.
>
> There's a compatibility issue with older gas where movq wasn't accepted,
> but movd was. Current gas allows either. There should be an investigation
> as to what gas version contains the fix, and if its older than the minimum
> required binutils version.
>
In INSTALL file minimal version is 2.20 which accoringing to
http://ftp.gnu.org/gnu/binutils/ is from
binutils-2.20.1.tar.bz2 26-Aug-2011 03:56 17M