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Re: Bytes order and words order
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Gabriel Dos Reis <gdr at integrable-solutions dot net>
- Cc: gcc at gcc dot gnu dot org, Richard dot Earnshaw at arm dot com
- Date: Fri, 23 Aug 2002 12:56:10 +0100
- Subject: Re: Bytes order and words order
- Organization: ARM Ltd.
- Reply-to: Richard dot Earnshaw at arm dot com
>
> Hi,
>
> Supports for floating-point data types in the C++ runtime system
> require me to know the bytes and words orders used by the target. I
> would like to have means for the front-end or driver to pass those
> information down to the library. I think a minimal path would be for
> CPP to define some macros like
>
> -D__TARGET_BYTES_ORDER__=__BIG_ENDIAN__ (or __LITTLE_ENDIAN__)
> -D__TARGET_WORDS_ORDER__=__BIG_ENDIAN__ (or __LITTLE_ENDIAN__)
>
> with, for example, __LITTLE_ENDIAN__ and __BIG_ENDIAN__ predefined to 0
> and 1 respectivelly. The same set of macros would be needed for the
> host in case of cross-compiling.
>
> I'll also need symbols for the floating-point model used.
>
> Thoughts? Neil?
Don't assume that the word-order of a floating-point number will be the
same as the word-order of an integral type. It isn't the case on the FPA
co-processor for the ARM for instance.
R.