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Re: ppc completely soft patches


On Mon, Nov 04, 2002 at 10:23:28AM -0800, Aldy Hernandez wrote:
> 
> > > For soft-float, gcc will emit calls to these in user space, and we want
> > > to use the library functions in libc, not the ones that come with
> > > libgcc.
> > 
> > Well, what's wrong with the functions in nof/libgcc.a? If gcc is used for 
> 
> libgcc is not only slower, but does not handle exceptions or rounding
> modes.
> 
> And even if it did handle, say rounding modes-- how would you set it?
> Glibc's <fenv.h> routines set that.
> 
> > linking they will always be used anyway, cause the link order is -lgcc -lc 
> > -lgcc? If the functions in libgcc.a are broken, libgcc should be fixed 
> > instead, or?
> 
> Yup, you are correct.  You'd have to add -lc to your command line to
> link libc first.  It's on my TODO list to hack gcc to link -lc first
> when switch foo-foo-bar is passed.

It seems to me (especially in light of the recent discussion of where
to put the new __abs* routines) that overriding libgcc's helpers in
glibc is asking for trouble.  Shouldn't fenv.h set them in a way that
libgcc can check, and the implementation be there?

I still don't understand what the FP emulator code is doing in glibc.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer


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