On Tue, Jul 26, 2011 at 8:22 AM, Kumar Gala <[email protected]> wrote: > > On Jul 26, 2011, at 8:59 AM, Richard Purdie wrote: > >> On Tue, 2011-07-26 at 08:47 -0500, Kumar Gala wrote: >>> On Jul 26, 2011, at 7:44 AM, Richard Purdie wrote: >>> >>>> Signed-off-by: Richard Purdie <[email protected]> >>>> --- >>>> meta/conf/machine/include/powerpc/arch-powerpc.inc | 45 >>>> +++++++++++++++++++- >>>> meta/conf/machine/include/tune-ppc603e.inc | 12 ++++- >>>> meta/conf/machine/include/tune-ppce300c2.inc | 12 ++++- >>>> meta/conf/machine/include/tune-ppce500.inc | 13 ++++-- >>>> meta/conf/machine/include/tune-ppce500mc.inc | 12 ++++- >>>> meta/conf/machine/include/tune-ppce500v2.inc | 12 ++++- >>>> 6 files changed, 88 insertions(+), 18 deletions(-) >>> >>> One thing I'm wondering about as we do this is the ability to pass >>> --with-cpu to gcc & [e]glibc configure to pickup proper optimized cfgs >>> & libs for a given target. >> >> As far as I can tell, gcc 4.x has no --with-cpu option. We pass the >> correct march and mtune options to the compiler at runtime through >> CFLAGS and friends. > > Hmm, gcc still supports this: > > http://gcc.gnu.org/install/configure.html > > --with-cpu=cpu > --with-cpu-32=cpu > --with-cpu-64=cpu > Specify which cpu variant the compiler should generate code for by default. > cpu will be used as the default value of the -mcpu= switch. This option is > only supported on some targets, including ARM, i386, M68k, PowerPC, and > SPARC. The --with-cpu-32 and --with-cpu-64 options specify separate default > CPUs for 32-bit and 64-bit modes; these options are only supported for i386, > x86-64 and PowerPC. > > http://gcc.gnu.org/install/specific.html > > powerpc-*-* > You can specify a default version for the -mcpu=cpu_type switch by using the > configure option --with-cpu-cpu_type.
thats only when you dont use -march -mtune -mcpu options but we use them always so using this configure option is not needed so much for us. Although I am not sure if the TARGET_CC_ARCH really makes into gcc runtime especially libgcc in that case --with-cpu will do things differently. > >> You're already found the way to pass configuration to *libc using values >> in TARGET_FPU to pickup the right configuration. >> >> Is there a use case we're missing? > > Yes, for [e]glibc we have optimized libc functions for a given / specific PPC > processor. So we need someway to tell configure this. > you need to use --with-cpu=CPU option at configure time. glibc configury does not grok the -mtune options otherwise. > - k > _______________________________________________ > Openembedded-core mailing list > [email protected] > http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core > _______________________________________________ Openembedded-core mailing list [email protected] http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core
