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From: "bugdal at aerifal dot cx" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug math/14412] Removal of sysdeps/x86_64/fpu/s_sincos.S causes regressions
Date: Mon, 29 Apr 2013 13:51:00 -0000 [thread overview]
Message-ID: <bug-14412-131-D4RRmF8LpA@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-14412-131@http.sourceware.org/bugzilla/>
http://sourceware.org/bugzilla/show_bug.cgi?id=14412
--- Comment #37 from Rich Felker <bugdal at aerifal dot cx> 2013-04-29 13:51:50 UTC ---
At the outer edges of that range, the error is "only" around 1000 ulps. This
isn't correct, but at least it's better than just having 4 or 5 bits of
precision (or none at all). Since the x87 internally uses a 66-bit
representation of pi, and doubles are 52-bit, I suspect precision starts to
trail off around 16384*pi, but it will be bad even for much smaller values when
the result is close to zero.
Experimentally, 0x1p18 seems to be the first power of two for which the result
is wrong within 15 decimal places, but 0x1p14*M_PI is already badly wrong (only
the first 4 decimal places are correct).
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next prev parent reply other threads:[~2013-04-29 13:51 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-26 21:08 [Bug math/14412] New: Removal of sysdeps/x86_64/fpu/s_sincos.S causes pdf rendering time regression markus at trippelsdorf dot de
2012-07-26 21:09 ` [Bug math/14412] " markus at trippelsdorf dot de
2012-07-26 21:14 ` markus at trippelsdorf dot de
2012-07-27 6:44 ` aj at suse dot de
2012-07-27 7:18 ` markus at trippelsdorf dot de
2012-07-27 12:33 ` markus at trippelsdorf dot de
2012-07-28 22:15 ` bugdal at aerifal dot cx
2012-08-03 3:51 ` carlos_odonell at mentor dot com
2012-08-09 10:14 ` markus at trippelsdorf dot de
2012-08-19 9:31 ` markus at trippelsdorf dot de
2012-08-19 9:37 ` [Bug math/14412] Removal of sysdeps/x86_64/fpu/s_sincos.S causes regressions markus at trippelsdorf dot de
2012-12-03 22:13 ` davem at davemloft dot net
2012-12-04 0:00 ` carlos at systemhalted dot org
2013-04-25 21:48 ` wbrana at gmail dot com
2013-04-25 23:35 ` carlos at redhat dot com
2013-04-25 23:58 ` bugdal at aerifal dot cx
2013-04-26 0:14 ` bugdal at aerifal dot cx
2013-04-26 2:55 ` siddhesh at redhat dot com
2013-04-26 3:08 ` bugdal at aerifal dot cx
2013-04-26 3:50 ` siddhesh at redhat dot com
2013-04-26 6:29 ` markus at trippelsdorf dot de
2013-04-26 6:40 ` jakub at redhat dot com
2013-04-26 10:00 ` siddhesh at redhat dot com
2013-04-26 11:31 ` joseph at codesourcery dot com
2013-04-26 11:33 ` joseph at codesourcery dot com
2013-04-26 11:42 ` siddhesh at redhat dot com
2013-04-26 13:52 ` bugdal at aerifal dot cx
2013-04-26 13:55 ` bugdal at aerifal dot cx
2013-04-26 15:07 ` joseph at codesourcery dot com
2013-04-26 15:20 ` wbrana at gmail dot com
2013-04-29 10:29 ` siddhesh at redhat dot com
2013-04-29 10:50 ` wbrana at gmail dot com
2013-04-29 11:55 ` bugdal at aerifal dot cx
2013-04-29 12:32 ` wbrana at gmail dot com
2013-04-29 13:21 ` Ondřej Bílka
2013-04-29 13:21 ` neleai at seznam dot cz
2013-04-29 13:28 ` bugdal at aerifal dot cx
2013-04-29 14:04 ` Ondřej Bílka
2013-04-29 13:32 ` bugdal at aerifal dot cx
2013-04-29 13:36 ` wbrana at gmail dot com
2013-04-29 13:44 ` siddhesh at redhat dot com
2013-04-29 13:51 ` bugdal at aerifal dot cx [this message]
2013-04-29 14:04 ` neleai at seznam dot cz
2013-04-29 14:19 ` siddhesh at redhat dot com
2013-04-29 14:29 ` markus at trippelsdorf dot de
2013-04-29 14:48 ` bugdal at aerifal dot cx
2013-04-29 16:29 ` Ondřej Bílka
2013-04-29 16:29 ` neleai at seznam dot cz
2013-04-29 17:30 ` bugdal at aerifal dot cx
2013-04-29 20:58 ` joseph at codesourcery dot com
2013-04-30 5:41 ` siddhesh at redhat dot com
2013-04-30 21:37 ` bugdal at aerifal dot cx
2013-05-01 22:25 ` bugdal at aerifal dot cx
2013-07-16 20:08 ` nshmyrev at yandex dot ru
2013-09-07 6:55 ` carlos at redhat dot com
2014-02-06 18:31 ` jsm28 at gcc dot gnu.org
2014-06-17 18:55 ` fweimer at redhat dot com
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