Re: glibc build problem...

[Oliver Falk <oliver at linux-kernel dot at>]

On 01/18/2011 08:19 PM, Matt Turner wrote:
> On Tue, Jan 18, 2011 at 5:39 PM, Oliver Falk<oliver@linux-kernel.at>  wrote:
> > Hi guys!
> >
> > Sorry for directly mailing you... But m/l don't work for me ATM.
>
> Added libc-ports@ for you. There's no reason not to mail it.
>
> > stubs.c: In function '__setfpucw':
> > stubs.c:47: warning: implicit declaration of function '_FPU_SETCW'
> > stubs.c: In function '__setfpucw':
> > stubs.c:47: warning: implicit declaration of function '_FPU_SETCW'
> > /root/rpmbuild/BUILD/glibc-2.11.2/build-alpha-linuxnptl/glibc-compat/libNoVersion_pic.a(stubs.os):
> > In function `__setfpucw':
> > /data/work/rpmbuild/BUILD/glibc-2.11.2/glibc-compat/stubs.c:47: undefined
> > reference to `_FPU_SETCW'
> > /data/work/rpmbuild/BUILD/glibc-2.11.2/glibc-compat/stubs.c:47: undefined
> > reference to `_FPU_SETCW'
> > collect2: ld returned 1 exit status
> > make[2]: ***
> > [/root/rpmbuild/BUILD/glibc-2.11.2/build-alpha-linuxnptl/glibc-compat/libNoVersion.so]
> > Error 1
> >
> >
> > Ideas?
> >
> > On other archs it's defined as some __asm__ volatile code... Actually not
> > the stuff I'm able to do...
> >
> > -of
>
> Lots of alpha patches went into glibc-2.12. Try that before you spend
> too much time trying to compile an older version.

These defines - as already said - have not been introduced in one of the 
later glibc versions.

However. I guess this does make sense (taken from 
sysdeps/unix/sysv/linux/alpha/setfpucw.c):

sysdeps/alpha/fpu/fpu_control.h:
/* Macros for accessing the hardware control word.  */
#define _FPU_GETCW(cw) __asm__ ("excb; mf_fpcr %0" : "=f"(cw));
#define _FPU_SETCW(cw) __asm__ volatile ("mt_fpcr %0; excb" : : "f"(cw));

Really, I have not much clue about asm :-) So if this is totally wrong, 
feel free to correct me. If not, it would be great if this could be 
included...

I'm not 100% sure if for _FPU_SETCW it is needed to also *save* FPCR. :-?

PLMK what you think.

-of

-of