Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.arch > #110516

Re: Calling conventions (particularly 32-bit ARM)

From Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups comp.arch
Subject Re: Calling conventions (particularly 32-bit ARM)
Date 2025-01-14 15:32 -0800
Organization None to speak of
Message-ID <87r0557z0k.fsf@nosuchdomain.example.com> (permalink)
References (9 earlier) <a0867899b693a1bc2579ec7cc25d676c@www.novabbs.org> <6DghP.566840$EYNf.141529@fx11.iad> <vm5r00$2e9ha$1@dont-email.me> <nGuhP.275371$2xE6.65834@fx18.iad> <vm6142$2fgsg$1@dont-email.me>

Show all headers | View raw

David Brown <david.brown@hesbynett.no> writes:
[...]
> I would say the key flag here is "-fno-math-errno" (which is included
> in -ffast-math).  While I personally think most floating point code
> could be used just as well with "-ffast-math", and it is certainly
> appropriate for my own code, others have significantly different
> opinions or experiences.  (That's fair enough.)  That one flag simply
> disables setting errno in maths functions that can (reasonably) be
> implemented inline as instructions, without affecting the results of
> any other floating point operations.
>
> But to my mind, this is /not/ a case of the POSIX programmer making
> the choice - it is an implementation-specific feature.  A C compiler
> might choose to always use errno, or never, or have some other control
> of the use of errno.  When you write "POSIX leaves it up to the
> programmer", I take that to mean POSIX specifies a function that lets
> you change the value of "math_errhandling".  That is quite different
> from saying "gcc has a flag that lets you choose".

math_errhandling is specified by ISO C, starting with C99.  POSIX merely
copies and refers to the ISO C requirements.  (POSIX might add some
requirements, but I haven't seen that.)  I suggest that POSIX is
irrelevant to this discussion.

As far as I can tell, there is no POSIX (or ISO C) function that changes
the value of math_errhandling.  In fact, such a function would violate
the ISO C rule that "The value of math_errhandling is constant for the
duration of the program.".

> (For my own use, I like the flag - I don't write POSIX code, I have
> never had any use for errno, and I want the compiler to generate as
> few instructions as it possibly can.)

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */

Back to comp.arch | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-06 14:57 +0100
  Re: Calling conventions (particularly 32-bit ARM) Theo <theom+news@chiark.greenend.org.uk> - 2025-01-06 15:23 +0000
    Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-07 09:22 +0100
  Re: Calling conventions (particularly 32-bit ARM) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-01-06 15:32 +0000
    Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-06 20:19 +0000
      Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-07 10:09 +0100
        Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-07 23:23 +0000
          Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-07 23:35 +0000
            Re: Calling conventions (particularly 32-bit ARM) "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-01-07 15:42 -0800
              Re: Calling conventions (particularly 32-bit ARM) "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-01-07 20:01 -0800
            Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-08 01:38 +0000
    Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-07 09:49 +0100
  Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-06 20:10 +0000
    Re: Calling conventions (particularly 32-bit ARM) antispam@fricas.org (Waldek Hebisch) - 2025-01-07 02:11 +0000
      Re: Calling conventions (particularly 32-bit ARM) Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-01-07 06:53 +0000
      Re: Calling conventions (particularly 32-bit ARM) Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-01-12 12:10 -0800
        Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-12 20:41 +0000
        Re: Calling conventions (particularly 32-bit ARM) antispam@fricas.org (Waldek Hebisch) - 2025-01-13 01:20 +0000
          Re: Calling conventions (particularly 32-bit ARM) Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-01-14 09:40 -0800
            Re: Calling conventions (particularly 32-bit ARM) Terje Mathisen <terje.mathisen@tmsw.no> - 2025-01-14 19:18 +0100
              Re: Calling conventions (particularly 32-bit ARM) Michael S <already5chosen@yahoo.com> - 2025-01-14 23:48 +0200
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-14 23:27 +0000
                Re: Calling conventions (particularly 32-bit ARM) John Levine <johnl@taugh.com> - 2025-01-15 03:31 +0000
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-15 16:50 +0000
                Re: Calling conventions (particularly 32-bit ARM) John Levine <johnl@taugh.com> - 2025-01-15 22:03 +0000
                Re: Calling conventions (particularly 32-bit ARM) antispam@fricas.org (Waldek Hebisch) - 2025-01-16 03:02 +0000
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-16 15:08 +0000
                Re: Calling conventions (particularly 32-bit ARM) antispam@fricas.org (Waldek Hebisch) - 2025-01-16 16:24 +0000
        Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-13 21:33 +0000
          Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-14 06:48 +0000
            Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-14 18:03 +0000
    Re: Calling conventions (particularly 32-bit ARM) George Neuner <gneuner2@comcast.net> - 2025-01-07 16:52 -0500
      Re: Calling conventions (particularly 32-bit ARM) Stefan Monnier <monnier@iro.umontreal.ca> - 2025-01-08 12:20 -0500
        Re: Calling conventions (particularly 32-bit ARM) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-01-09 08:38 +0000
          Re: Calling conventions (particularly 32-bit ARM) Stefan Monnier <monnier@iro.umontreal.ca> - 2025-01-13 10:55 -0500
      Re: Calling conventions (particularly 32-bit ARM) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-01-27 17:09 -0800
        Re: Calling conventions (particularly 32-bit ARM) George Neuner <gneuner2@comcast.net> - 2025-01-28 22:53 -0500
          Re: Calling conventions (particularly 32-bit ARM) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-02-14 20:40 -0800
            Re: Calling conventions (particularly 32-bit ARM) George Neuner <gneuner2@comcast.net> - 2026-02-17 15:35 -0500
              Re: Calling conventions (particularly 32-bit ARM) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-03-14 09:34 -0700
                Re: Calling conventions (particularly 32-bit ARM) George Neuner <gneuner2@comcast.net> - 2026-03-24 17:20 -0400
    Re: Calling conventions (particularly 32-bit ARM) Stefan Monnier <monnier@iro.umontreal.ca> - 2025-01-08 12:34 -0500
      Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-08 20:19 +0000
      Re: Calling conventions (particularly 32-bit ARM) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-01-08 22:08 +0000
        Re: Calling conventions (particularly 32-bit ARM) Stefan Monnier <monnier@iro.umontreal.ca> - 2025-01-08 18:20 -0500
          Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-09 00:11 +0000
          Re: Calling conventions (particularly 32-bit ARM) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-01-09 07:23 +0000
            Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-09 10:07 +0000
              Re: Calling conventions (particularly 32-bit ARM) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-01-10 08:24 +0000
            Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-09 20:48 +0000
              Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-09 21:23 +0000
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-10 01:08 +0000
                Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-10 09:19 +0000
            Re: Calling conventions (particularly 32-bit ARM) antispam@fricas.org (Waldek Hebisch) - 2025-01-10 08:33 +0000
              Re: Calling conventions (particularly 32-bit ARM) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-01-10 10:25 +0000
                Re: Calling conventions (particularly 32-bit ARM) John Levine <johnl@taugh.com> - 2025-01-10 15:17 +0000
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-13 02:10 +0000
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-13 14:19 +0000
                Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-13 18:02 +0000
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-13 19:00 +0000
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-13 21:53 +0000
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-13 22:02 +0000
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-13 22:40 +0000
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-14 02:32 +0000
                Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-14 15:08 +0100
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-14 14:22 +0000
                Re: Calling conventions (particularly 32-bit ARM) Michael S <already5chosen@yahoo.com> - 2025-01-14 16:41 +0200
                Re: Calling conventions (particularly 32-bit ARM) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-01-14 18:02 +0000
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-14 18:15 +0000
                Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-14 18:19 +0000
                Re: Calling conventions (particularly 32-bit ARM) Terje Mathisen <terje.mathisen@tmsw.no> - 2025-01-14 19:39 +0100
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-14 19:14 +0000
                Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-14 20:01 +0000
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-14 22:05 +0000
                Re: Calling conventions (particularly 32-bit ARM) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-01-14 15:23 -0800
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-14 23:39 +0000
                Re: Calling conventions (particularly 32-bit ARM) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-01-14 16:59 -0800
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-14 23:40 +0000
                Re: Calling conventions (particularly 32-bit ARM) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-01-14 17:11 -0800
                Re: Calling conventions (particularly 32-bit ARM) Michael S <already5chosen@yahoo.com> - 2025-01-15 00:09 +0200
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-14 19:08 +0000
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-14 19:24 +0000
                Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-14 20:31 +0000
                Re: Calling conventions (particularly 32-bit ARM) Michael S <already5chosen@yahoo.com> - 2025-01-14 23:13 +0200
                Re: Calling conventions (particularly 32-bit ARM) mitchalsup@aol.com (MitchAlsup1) - 2025-01-15 00:47 +0000
                Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-14 06:20 +0000
                Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-14 15:05 +0100
                Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-14 14:39 +0000
                Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-14 16:50 +0100
                Re: Calling conventions (particularly 32-bit ARM) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-01-14 15:32 -0800
                Re: Calling conventions (particularly 32-bit ARM) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-01-14 00:14 -0800
              Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-10 14:43 +0000
            Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-10 18:39 +0100
              Re: Calling conventions (particularly 32-bit ARM) scott@slp53.sl.home (Scott Lurndal) - 2025-01-10 18:39 +0000
                Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-12 14:55 +0100
              Re: Calling conventions (particularly 32-bit ARM) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-10 19:19 +0000
                Re: Calling conventions (particularly 32-bit ARM) David Brown <david.brown@hesbynett.no> - 2025-01-12 14:59 +0100

csiph-web