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Re: [PATCH] Implement fma correctly
- From: Richard Henderson <rth at twiddle dot net>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: libc-alpha at sources dot redhat dot com
- Date: Tue, 12 Oct 2010 15:02:31 -0700
- Subject: Re: [PATCH] Implement fma correctly
- References: <20101012191605.GQ2652@sunsite.ms.mff.cuni.cz>
On 10/12/2010 12:16 PM, Jakub Jelinek wrote:
> Tested on x86_64-linux, it is very well possible it won't work correctly
> on i686 due to excess precision.
Given that you're already manipulating the status word, you
could go ahead and force 53-bit rounding at the same time
with minimal extra overhead. Of course, feupdateenv does
not reset the rounding size to match. You'd have to either
open-code that function in order avoid doing extra work,
or add new helper functions.
r~