Re: Re: Debian powerpc binary compatibility?
Hello Xavier,
> may be you can try apt-build ?
>
> $ cat /etc/apt/apt-build.conf
> build-dir = /var/cache/apt-build/build
> repository-dir = /var/cache/apt-build/repository
> Olevel = -O3
> march = -march=pentium2
> mcpu = -mcpu=pentium2
> options =
>
> As you can see, there you can rebuild packages in an automatic way with
> whatever option you need.
>
I see, thanks.
However, the auxiliary math routins in libgcc.a (.so) will be the same, and
not optimized for the given CPU type.
Gcc compiler should be build with "multilib" support enabled, in this case
the build provides specialized libgcc.a and startup .o modules for each
possible "-mcpu", in separate subdirs in /usr/lib/gcc/<arch>/gcc-<version>/<cpu>.
(I wonder - is it the big gain having them optimized?)
Thanks a lot for reply.
Regards,
Sergei
> Hope it will help, xavier
>
> ----------------original message-----------------
> De: "brian m. carlson" sandals@crustytoothpaste.net
> A: debian-powerpc@lists.debian.org
> Date: Fri, 17 Sep 2010 16:24:41 +0000
> -------------------------------------------------
>
>
> > On Fri, Sep 17, 2010 at 01:48:19PM +0400, Sergei Poselenov wrote:
> >> - What exact target CPU it is built for? I see here
> >> http://www.debian.org/ports/powerpc/inst/install the list of
> >> supported machines, but how can I understand will the Debian binaries
> >> work on my board with the specific CPU?
> >> Is it possible, knowing only the specific CPU type (440, 603, 8540,
> >> 8560, etc) to say will it run Debian PowerPC Distro or not?
> >> (I understand that there should be a kernel supporting the specific
> >> board; I'm rather interested in the instructions set used by GCC to
> >> build the binary images for Debian powerpc distro. In short - what
> >> "-mcpu=" GCC option is used for build?)
> >
> > I believe "-mcpu=generic" is used, except for perhaps certain kernels.
> > As you pointed out, if there's a kernel for it, Debian powerpc will run
> > on that type of chip. There may be specially-compiled versions of some
> > packages that use Altivec, but there should be a generic version for
> > those as well.
> >
> > You can try running "gcc -v" and see what host, build, target, and
> > with-tune are set to.
> >
> >> - We are considering to rebuild the Debian distribution, to
> >> tune the packages for the specific CPU type (enable hardware FP
> >> support, etc).
> >> I now the Debian powerpc distro is built natively. Are there any
> >> details of the build process available, so we could use it in our
> >> build system?
> >
> > Normally when you build a package with dpkg-buildpackage, it sets
> > certain environment variables to a default value (for example, CFLAGS=-g
> > -O2). You may be able to modify that slightly for your needs. Note
> > that that doesn't guarantee that the package in question won't override
> > it.
> >
> > --
> > brian m. carlson / brian with sandals: Houston, Texas, US
> > +1 832 623 2791 | http://www.crustytoothpaste.net/~bmc | My opinion only
> > OpenPGP: RSA v4 4096b: 88AC E9B2 9196 305B A994 7552 F1BA 225C 0223
> > B187
> >
>
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