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Re: fr30 FP format question
- From: Joel Sherrill <joel dot sherrill at OARcorp dot com>
- To: Toon Moene <toon at moene dot indiv dot nluug dot nl>
- Cc: gcc at gcc dot gnu dot org
- Date: Mon, 29 Apr 2002 09:19:43 -0500
- Subject: Re: fr30 FP format question
- Organization: OAR Corporation
- References: <3CCAFFF2.B6B60F19@OARcorp.com> <3CCD4D98.EE1E9D6C@moene.indiv.nluug.nl>
- Reply-to: joel dot sherrill at OARcorp dot com
Toon Moene wrote:
>
> Joel Sherrill wrote:
>
> > FR30 can't build fortran because this is being tripped
> > in gcc/f/target.h:
> >
> > /* For now, g77 requires the ability to determine the exact bit pattern
> > of a float on the target machine. (Hopefully this will be changed
> > soon). Make sure we can do this. */
> >
> > #if !defined (REAL_ARITHMETIC) \
> > && ((TARGET_FLOAT_FORMAT != HOST_FLOAT_FORMAT) \
> > || (FLOAT_WORDS_BIG_ENDIAN != HOST_FLOAT_WORDS_BIG_ENDIAN))
> > #error "g77 requires ability to access exact FP representation of target
> > machine
> > "
> > #endif
> >
> > The fr30 appears to only have software floating point based upon
> > fr30/t-fr30 so I was thinking this had to be easy to fix but
> > don't know precisely what I am looking for to compare against. :(
> >
> > Could someone point me in the right direction? Thanks.
>
> As far as I can see, the only comparison in the above conditional that's
> not true is FLOAT_WORDS_BIG_ENDIAN != HOST_FLOAT_WORDS_BIG_ENDIAN.
>
> This is so, because the fr30 is a big-endian machine (which means that
> its FLOATs will be big-endian also, by default), whereas the ix86, from
> which you want to cross-compile, is a little-endian machine, with
> little-endian FLOATs.
>
> This means that you should be able to build the cross-compiler on a
> big-endian machine, like powerpc, sparc, mips or s390 ...
But I can build this library for any number of other CPUs. I can
do x86 to arm, powerpc, mips, sparc, etc. I think most of those
are big endian by default.
> --
> Toon Moene - mailto:toon@moene.indiv.nluug.nl - phoneto: +31 346 214290
> Saturnushof 14, 3738 XG Maartensdijk, The Netherlands
> Maintainer, GNU Fortran 77: http://gcc.gnu.org/onlinedocs/g77_news.html
> Join GNU Fortran 95: http://g95.sourceforge.net/ (under construction)
--
Joel Sherrill, Ph.D. Director of Research & Development
joel@OARcorp.com On-Line Applications Research
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