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Re: The perennial i386 floating-point rounding issue...
- From: Richard Henderson <rth at redhat dot com>
- To: Stephen L Moshier <steve at moshier dot net>
- Cc: mike stump <mrs at windriver dot com>, gcc at gcc dot gnu dot org, zack at codesourcery dot com
- Date: Mon, 10 Jun 2002 17:56:14 -0700
- Subject: Re: The perennial i386 floating-point rounding issue...
- References: <Pine.LNX.4.33.0206101956380.15319-100000@moshier.net>
On Mon, Jun 10, 2002 at 08:03:26PM -0400, Stephen L Moshier wrote:
> Or maybe we should offer a way to set it ourselves.
This is (in theory) very easy to do. See optimize_mode_switching
and NORMAL_MODE. It should be relatively easy to modify the
existing optimize_mode_switching macros to add bits to control
the rounding mode.
I would be very open to a patch that optionally enabled setting
the rounding precision bits for the computation.
And on a related point, while I may have once argued against
spilling in 80-bit mode (when not controling computation precision),
I've been convinced that it's a mistake. So if someone wants to
work on that as well, please do so. It'll be a bit harder though...
r~