From: Brad Lucier <lucier@math.purdue.edu>
To: burley@gnu.org, egcs@egcs.cygnus.com
Cc: lucier@math.purdue.edu
Subject: Re: FWD: FLOATING-POINT CONSISTENCY, -FFLOAT-STORE, AND X86
Date: Thu, 17 Dec 1998 11:27:00 -0000 [thread overview]
Message-ID: <199812171927.OAA03931@polya.math.purdue.edu> (raw)
I agree with Craig (I think ;-).
To get consistent, predictable, useable floating-point results, it is
absolutely necessary that spilled floating-point registers be stored in
memory in a format such that spilling and reading a value back into a
register does not change one bit (in the technical sense) of the number.
If that means spilling FP registers to 80 bit temporaries aligned to
128-bit (or 64bit) boundaries, then so be it.
I say this as someone who has built highly accurate elementary function
routine libraries, together with test libraries for those routines, built
test libraries for last-bit accuracy floating-point IO routines, etc.
The programmer needs absolute control over the precision and range of
all results, including intermediate results, for him/her to be successful
at things like this.
Brad Lucier lucier@math.purdue.edu
next reply other threads:[~1998-12-17 11:27 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-12-17 11:27 Brad Lucier [this message]
1998-12-17 14:51 ` Marc Lehmann
1998-12-19 0:17 ` Craig Burley
1998-12-19 6:42 ` Emil Hallin
1998-12-19 14:26 ` Dave Love
-- strict thread matches above, loose matches on Subject: below --
1998-12-17 14:38 Toon Moene
1998-12-17 15:30 ` Harvey J. Stein
1998-12-18 1:54 ` Toon Moene
1998-12-18 3:05 ` Harvey J. Stein
1998-12-18 9:01 ` Toon Moene
1998-12-18 15:59 ` Richard Henderson
1998-12-18 13:26 ` Marc Lehmann
1998-12-18 12:50 ` Dave Love
1998-12-17 14:37 tprince
1998-12-17 15:15 ` Stephen L Moshier
1998-12-16 13:52 Toon Moene
1998-12-17 10:06 ` Craig Burley
1998-12-17 12:16 ` Harvey J. Stein
1998-12-19 0:29 ` Craig Burley
1998-12-17 11:20 ` Dave Love
1998-12-15 12:24 Toon Moene
1998-12-15 12:55 ` Joe Buck
1998-12-15 15:05 ` Edward Jason Riedy
1998-12-16 10:05 ` Craig Burley
1998-12-15 12:10 Geert Bosch
1998-12-15 13:09 ` Jeffrey A Law
1998-12-15 1:45 Geert Bosch
1998-12-15 3:34 ` Harvey J. Stein
1998-12-16 10:36 ` Craig Burley
1998-12-16 12:47 ` Harvey J. Stein
1998-12-17 10:22 ` Craig Burley
1998-12-17 14:54 ` Marc Lehmann
1998-12-19 0:27 ` Craig Burley
1998-12-19 5:06 ` Stephen L Moshier
1998-12-15 6:43 ` Stephen L Moshier
1998-12-16 10:14 ` Craig Burley
1998-12-15 9:29 ` Joe Buck
1998-12-15 10:14 ` Jeffrey A Law
1998-12-16 8:32 ` Sylvain Pion
1998-12-16 9:20 ` Craig Burley
1998-12-13 18:23 Stephen L Moshier
1998-12-14 1:52 ` Harvey J. Stein
1998-12-14 14:56 ` Edward Jason Riedy
1998-12-14 17:20 ` Joe Buck
1998-12-14 18:51 ` Edward Jason Riedy
1998-12-14 21:54 ` Craig Burley
1998-12-15 14:31 ` Edward Jason Riedy
1998-12-15 17:11 ` Jamie Lokier
1998-12-16 0:26 ` Harvey J. Stein
1998-12-16 9:33 ` Craig Burley
1998-12-16 12:18 ` Harvey J. Stein
1998-12-16 9:38 ` Craig Burley
1998-12-16 12:25 ` Marc Lehmann
1998-12-16 12:50 ` Tim Hollebeek
1998-12-16 13:04 ` Harvey J. Stein
1998-12-16 14:01 ` Marc Lehmann
1998-12-17 11:26 ` Dave Love
1998-12-17 15:06 ` Marc Lehmann
1998-12-18 12:50 ` Dave Love
1998-12-19 14:09 ` Marc Lehmann
1998-12-20 11:28 ` Dave Love
1998-12-20 11:24 ` Dave Love
1998-12-16 23:11 ` Joern Rennecke
1998-12-17 6:07 ` Jamie Lokier
1998-12-14 22:54 ` Craig Burley
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