[oe] gcc disable-libunwind-exceptions, VFP, iWMMXt, crunch - nokia800, mx31ads, etc

[Khem Raj]

On Mon, Mar 31, 2008 at 11:10 PM, Hasjim Williams
<openembedded-devel at lists.futaris.org> wrote:
> Hi All,
>
>  I was recently looking in gcc-cross-4.2.2.bb and 4.3.0.bb and noticed
>  that in our EXTRA_OECONF we have:
>
>  --disable-libunwind-exceptions
>
>  Won't this cause a problem for a VFP system (when an exception occurs),

AFAIK this option is used if you want gcc to use libunwind to handle exceptions.

>  i.e. mx31ads, nokia800?
>  e.g. libunwind.S in gcc/config/arm has some specific functions to
>  save/restore VFP and iWMMXt registers...
>

that should work on EABI. I am not so sure about OABI.

>  Also, I couldn't build glibc-intermediate (with system-wide iwmmxt) with
>  the tag enabled, when building with binutils-2.18, gcc-4.3.0 and
>  glibc-2.6.1 ...

what was the error ?

>
>  How does the TARGET_FPU_arm = "hard" overcome this on nokia800, mx31ads,

Its machine specific  e.g. look at ./machine/nokia800.conf
thats where it sets the fpu type which is then used by glibc
"get_glibc_fpu_setting" to determine if it use use hard or soft fp.


>  etc?  Are we only building with-float in certain packages, and using
>  softfp float-abi otherwise?
>
>  Does this mean for a MaverickCrunch system (with system-wide FPU
>  enabled), we should be setting TARGET_FPU_arm = "hard" too?
>
>  What about for a PXA27x system with a iWMMXt coprocessor (and
>  system-wide iwmmxt) ???  It should be using soft-float, but it should
>  have libunwind-exceptions enabled (I think) because of the code in
>  libunwind.S...
>
>
>  _______________________________________________
>  Openembedded-devel mailing list
>  Openembedded-devel at lists.openembedded.org
>  http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-devel
>