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Date: Fri, 13 Mar 1998 13:59:01 +0200 (EET)
From: Tuukka Toivonen <tuukkat AT ees2 DOT oulu DOT fi>
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To: Marc Lehmann <pcg AT goof DOT com>
cc: beastium <beastium-list AT Desk DOT nl>
Subject: Re: paranoia & extra precision [was -fno-float-store in pgcc]
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Sender: Marc Lehmann <pcg AT goof DOT com>
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On Thu, 12 Mar 1998, Marc Lehmann wrote:

>yeah, it's even worse.. so you have sth. between 53 and 80 bits of precision.

- If you want extended precision -> store values in memory with 10 bytes.
  You'll get always 80 bits precision.
- If you want to use `double' format with some extra precision,
  just set high precision on and use doubles.
- If you want IEEE-compliance, set FPU to low precision and everything is
  right again.

The hardware makes all of this possible. Don't blame FPU if C compiler can
not do it (again, I don't say it couldn't; I don't know).

>(slow code). to my knowledge, no compiler goes the slow way
>by default ;)

It doesn't do it by default.

You are saying that if user wants low precision from _transcendental_
functions, it will be slow code? Transcendental functions are slow anyway
so to round them to 64-bitness doesn't make code slower almost at all.

For functions being not transcendental, that doesn't make sense at all
since lower precision is faster.

>pragma = nono ;) until c9x adds the _Pragma syntax, #pragma's are just
>useless.

I think that I read somewhere why #pragma's shouldn't be use. I think it
would be nice way to 'hint' the compiler... I don't understand what's the
problem with them? Everyone except GCC uses them. (Well... at least
Borland/Watcom :)

--
| Tuukka Toivonen <tuukkat AT ee DOT oulu DOT fi>       [PGP public key
| Homepage: http://www.ee.oulu.fi/~tuukkat/       available]
| Try also finger -l tuukkat AT ee DOT oulu DOT fi
| Studying information engineering at the University of Oulu
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