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Date:      Wed, 14 Jul 1999 07:55:25 +0100 (BST)
From:      Doug Rabson <dfr@nlsystems.com>
To:        John Polstra <jdp@polstra.com>
Cc:        simokawa@sat.t.u-tokyo.ac.jp, alpha@freebsd.org
Subject:   Re: alpha/12623: strtod(3) FPE on alphaev56
Message-ID:  <Pine.BSF.4.10.9907140754120.58023-100000@salmon.nlsystems.com>
In-Reply-To: <199907131711.KAA36944@vashon.polstra.com>

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On Tue, 13 Jul 1999, John Polstra wrote:

> In article <14219.25613.478914.44162J@ett.sat.t.u-tokyo.ac.jp>,
> Hidetoshi Shimokawa  <simokawa@sat.t.u-tokyo.ac.jp> wrote:
> > 
> > /usr/src/lib/libc/stdlib/strtod.c seems broken on alpha in three ways.
> > 
> > 1) IEEE_8087 should be defined instead of IEEE_MC68k.
> > 
> > 2) It assumes long is 32bit, but long is 64bit on alpha.
> > 	s/unsigned long/u_int32_t/, s/long/int32_t/.
> > 
> > 3) It generates denormal numbers which can not be treaded by the hardware
> >    on alpha. It should be compiled with the option
> >    `-mtrap-precision=i -mfp-trap-mode=su' to enable software completion.
> 
> Yes, or the equivalent "-mieee".  In my opinion, all of the libraries
> (if not the whole world) should be compiled that way.  In fact, this
> option should be the default.  Users who wanted a little extra speed
> and who knew what they are doing could turn it off.

I agree (at least as far as the libraries go). Setting it as default would
be easy but there are performance implications. On the other hand, the
only applications whose performance is affected are ones using floating
point..

--
Doug Rabson				Mail:  dfr@nlsystems.com
Nonlinear Systems Ltd.			Phone: +44 181 442 9037




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