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Re: long double format on I!64
- From: Bo Thorsen <bo at sonofthor dot dk>
- To: Gabriel Dos Reis <gdr at integrable-solutions dot net>, gcc at gcc dot gnu dot org
- Cc: Jim Wilson <wilson at redhat dot com>
- Date: Thu, 29 Aug 2002 08:34:45 +0200
- Subject: Re: long double format on I!64
- References: <m33csyprou.fsf@soliton.integrable-solutions.net>
On Thursday 29 August 2002 00:02, Gabriel Dos Reis wrote:
> Hi,
>
> I've been reviewing the fundamental data types format as
> communicated to V3 sources. due to some mismatch in data, we're now
> getting some information directly from the compiler. See
>
> http://gcc.gnu.org/ml/gcc-patches/2002-08/msg01672.html
>
> In the file
>
> libstdc++-v3/config/cpu/ia64/cpu_limits.h
>
> I see the following
>
> // While sizeof(long double) == 16, the format is the same as the x86.
> #define __glibcpp_long_double_bits 80
>
> I don't know how exactly I should interpret that since 80 bits don't
> make 16 bytes. I guess that means some bits are ignored. If so I need
> to know exactly which ones.
It's like x86, just with 6 bytes padding instead of 2. So the first 10 bytes
are the double.
BTW, x86-64 does exactly the same.
Bo.
--
Bo Thorsen | Praestevejen 4
Free software developer | 5290 Marslev
SuSE Labs | Denmark