[gentoo-embedded] glibc and softfloat

[gentoo-embedded] glibc and softfloat

[Daniel Glaser]

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Hello,

last days I was trying to setup an embedded environment for some ppc405.

I had great succes, because the tree was chrootable and bash was
working properly. But when it came to portage, I encountered strange
problems with math functions.

After long traceback, I found, that glibc and gcc have problems with
softfloat. (for glibc --without-fp is the right configure option for
my system, but currently it is not directly supportet by the ebuild,
got it in through EXTRA_ECONF="--without-fp")

My first try was to build with powerpc-unknown-linux-gnu, now I now,
that I need powerpc-softfloat-linux-gnu, this is, where it get's
difficult.

Another thing is, that -msoft-float and -mlong-double-128 are not
supported (many many warnings), but used within the Gentoo ebuild.
Perhaps -m128bit-soft-float is the one the programmers wanted, but in
my opinion it is also not the right choice.

The Problems with glibc(2.4) and gcc (4.1.1 and 4.2) are discussed in
this bugreport http://sourceware.org/bugzilla/show_bug.cgi?id=2749.
Some patches are also discussed and attached in this bugreport.

I would be very greatful, if somebody takes a look at this and give me
some
feedback with your opinion, if, how and how fast this could be solved
within Gentoo and crossdev.

- -themole
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Re: [gentoo-embedded] glibc and softfloat

[Mike Frysinger]

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On Tuesday 26 September 2006 12:28, Daniel Glaser wrote:
> After long traceback, I found, that glibc and gcc have problems with
> softfloat. (for glibc --without-fp is the right configure option for
> my system, but currently it is not directly supportet by the ebuild,
> got it in through EXTRA_ECONF="--without-fp")

if you use a target of *-softfloat-* the glibc ebuild will add --without-fp 
and the gcc ebuild will add --with-float=soft

> Another thing is, that -msoft-float and -mlong-double-128 are not
> supported (many many warnings), but used within the Gentoo ebuild.
> Perhaps -m128bit-soft-float is the one the programmers wanted, but in
> my opinion it is also not the right choice.

the Gentoo ebuild does nothing of the sort ... this is all in the glibc build 
system itself

glibc-2.4 on ppc will require gcc-4.1.x ... anything older is not supported 
and i certainly wont waste any time on it

> The Problems with glibc(2.4) and gcc (4.1.1 and 4.2) are discussed in
> this bugreport http://sourceware.org/bugzilla/show_bug.cgi?id=2749.
> Some patches are also discussed and attached in this bugreport.

well, once upstream settles on something i have no problem cutting a patch 
from their cvs and putting into our glibc-2.4 patchset ... but i wouldnt 
really want to do anything until they've settled on a solution first
-mike

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