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Re: Mathematical Funktions for H8/300h - double ?
- To: crossgcc@cygnus.com
- Subject: Re: Mathematical Funktions for H8/300h - double ?
- From: Jeffrey A Law <law@cygnus.com>
- Date: Tue, 22 Jun 1999 04:57:57 -0600
- Reply-To: crossgcc@cygnus.com
In message <199906220925.MAA10820@laatikko.saunalahti.fi>you write:
> Yes, the 'double' is the same 32-bit type as 'float'. The reason seems
> to be that a 8/16-bit processor is not expected to be used in 'number
> crunching'. Handling 64-bit floating point numbers will be quite slow.
>
>
> I cannot say if adding the support for a real 64-bit 'double' needs more
> than changing the fiddlings with the 'fp-bit.c'/'dp-bit.c' (if the '.md'
> file generates code for 64-bit entities like 64-bit 'long' and 'double').
> Has anyone tried adding the 64-bit 'double' ?
GCC's FP support libraries require a 64bit integer type internally in the
double precision floating point emulation code. (see config/fp-bit.c).
And if you poke around with the H8 tools, you'll find that they do not
support integer types > 32bits wide. Last I looked (1995 or so) adding
support for 64bit integer types was nontrivial, especially on the low
end of the H8 family of processors.
jeff
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