From: Eli Zaretskii <eliz@elta.co.il>
Cc: emacs-devel@gnu.org
Subject: Re: (elisp)Numbers
Date: 26 Oct 2003 08:04:31 +0200 [thread overview]
Message-ID: <uismch6vk.fsf@elta.co.il> (raw)
In-Reply-To: <E1ADWrm-0007jq-Ax@fencepost.gnu.org> (message from Richard Stallman on Sat, 25 Oct 2003 18:26:38 -0400)
> From: Richard Stallman <rms@gnu.org>
> Date: Sat, 25 Oct 2003 18:26:38 -0400
>
> Here's the code I see with "gcc -E -O2" on fencepost (I reformatted it
> for better readability):
>
> extern __inline double sqrt ( double __x)
> {
> register double __result;
> __asm __volatile__ ( "fsqrt" : "=t" (__result) : "0" (__x) );
> return __result;
> }
>
> 1. where does this code come from? which file in which package?
This is part of cpp's output when I run on floatfns.c the same
command as when it is compiled into floatfns.o, but with -c replaced
with -E. For the build on fencepost, this is the command I ran:
gcc -E -D_BSD_SOURCE -Demacs -DHAVE_CONFIG_H -I. -I/home/e/eliz/emacs/src -D_BSD_SOURCE -O2 floatfns.c | less -ci
If you omit -O2, the inline expansion of `sqrt' doesn't appear in the
output, so the library function is called.
The expansion itself seems to come from
/usr/include/bits/mathinline.h, which is part of glibc, since
immediately before the above snippet, I see this line:
# 438 "/usr/include/bits/mathinline.h" 3
mathinlines.h has this near line 438:
__inline_mathopNP (sqrt, "fsqrt")
which, after a series of macro expansions, eventually expands into
the above inline definition of `sqrt'.
Similar things happen with other math functions. It sounds like
under -O2 no math function ever sets errno.
> 2. i see that my CFLAGS setting to turn off inlining got lost
> when i reran configure. so i put that back in and recompiled,
> and it went away.
What went away? You mean that Emacs did throw a domain error when
floatfns.c was compiled without optimizations?
Anyway, we do want floatfns.c to be compiled with optimization and
still DTRT, right?
next prev parent reply other threads:[~2003-10-26 6:04 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-21 2:29 (elisp)Numbers Luc Teirlinck
2003-10-21 5:38 ` (elisp)Numbers Eli Zaretskii
2003-10-22 9:26 ` (elisp)Numbers Richard Stallman
2003-10-22 15:51 ` (elisp)Numbers Eli Zaretskii
2003-10-22 9:25 ` (elisp)Numbers Richard Stallman
2003-10-22 11:36 ` (elisp)Numbers Andreas Schwab
2003-10-22 15:42 ` (elisp)Numbers Eli Zaretskii
2003-10-23 18:38 ` (elisp)Numbers Richard Stallman
2003-10-24 8:43 ` (elisp)Numbers Andreas Schwab
2003-10-24 13:50 ` (elisp)Numbers Eli Zaretskii
2003-10-24 22:15 ` (elisp)Numbers Eli Zaretskii
2003-10-25 22:26 ` (elisp)Numbers Richard Stallman
2003-10-26 6:04 ` Eli Zaretskii [this message]
2003-10-27 7:02 ` (elisp)Numbers Richard Stallman
2003-10-27 19:56 ` (elisp)Numbers Eli Zaretskii
2003-10-27 21:46 ` (elisp)Numbers Andreas Schwab
2003-10-28 5:48 ` (elisp)Numbers Eli Zaretskii
2003-10-28 6:40 ` (elisp)Numbers Lars Brinkhoff
2003-10-28 20:03 ` (elisp)Numbers Eli Zaretskii
2003-10-28 20:40 ` (elisp)Numbers Richard Stallman
2003-10-24 13:38 ` (elisp)Numbers Eli Zaretskii
2003-10-24 22:04 ` (elisp)Numbers Eli Zaretskii
-- strict thread matches above, loose matches on Subject: below --
2003-10-04 15:36 (elisp)Numbers Luc Teirlinck
2003-10-07 19:57 ` (elisp)Numbers Eli Zaretskii
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