[Fwd: Re: [PATCH 1 of 3] arch: s390 and 390x glibc patch]

Yann E. MORIN yann.morin.1998@anciens.enib.fr
Sun Nov 15 00:37:00 GMT 2009


On Saturday 14 November 2009 17:28:26 Mike Frysinger wrote:
> > > > Mike Frysinger wrote:
> > > > >under Gentoo, a bunch of cache vars
> > > > >are forced just for the headers step as there is no compiler to test.
> > > > > those include mlong double tests.
> > > > >	libc_cv_mlong_double_128=yes
> > > > >	libc_cv_mlong_double_128ibm=yes
> these are settings that should always be there and the user shouldnt be forced 
> to configure themselves.  it also isnt specific to s390 ... it comes up with 
> ppc targets too.
> for the headers step, it's safe to export these all the time for all targets.  
> we've been doing this in gentoo for quite a long time now.

You mean unconditionally? On my x86_64 machine, debian lenny:
- in 64-bit mode: sizeof( long double ) = 16 bytes = 128 bits
- in 32-bit mode: sizeof( long double ) = 12 bytes =  96 bits

So, does it really makes sense to _unconditionnally_ set long-double-128?
The gcc man page says that on x86 (32-bit) the ABI specifies a size of
96 bits for long double.

Also, what does long-double-128ibm means?

Regards,
Yann E. MORIN.

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