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Re: The perennial i386 floating-point rounding issue...
- From: Stephen L Moshier <steve at moshier dot net>
- To: mike stump <mrs at windriver dot com>
- Cc: <gcc at gcc dot gnu dot org>, <zack at codesourcery dot com>
- Date: Mon, 10 Jun 2002 20:03:26 -0400 (EDT)
- Subject: Re: The perennial i386 floating-point rounding issue...
> Or, maybe we are just required to recommend the user set the 64 bit
> rounding mode thang?
Or maybe we should offer a way to set it ourselves.
Some years ago one of the Next people implemented a way for gcc to
keep track of the fpu precision setting. I don't know how well it worked
then or how practical it would be now, but I think many users would
be happier if double meant double and long double meant long double.
The vast majority of the user problems like this that I have analyzed
involve an innocent-looking program that does a compare operation
to an extra-precise register value. In other words, the most common
problem is not that we truncate values but that we fail to truncate
values.