Re: Calling conventions (particularly 32-bit ARM)

From	Stefan Monnier <monnier@iro.umontreal.ca>
Newsgroups	comp.arch
Subject	Re: Calling conventions (particularly 32-bit ARM)
Date	2025-01-08 18:20 -0500
Organization	A noiseless patient Spider
Message-ID	<jwvr05cq4tx.fsf-monnier+comp.arch@gnu.org> (permalink)
References	<vlgngv$1ks4a$1@dont-email.me> <4903307dfcce354508c9fc016a4c1ea1@www.novabbs.org> <jwv34htql17.fsf-monnier+comp.arch@gnu.org> <2025Jan8.230846@mips.complang.tuwien.ac.at>

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> ABI calling conventions tend to be designed to support at least C,
> including varargs and often also tolerant of differences between the
> number of arguments in the caller and callee.

I can agree that it's important to support those use-cases (varargs
obviously, mismatched arg numbers less so), but I think the focus of
optimization of the ABI should be calls to functions known to take the
exact same number of arguments (after all, even in C we normally know
the prototype of the called function; only sloppy ancient C calls
functions without proper declarations), even if it comes at the cost of
using different calling conventions for the two cases.

>>But in any case, I suspect there are also diminishing returns at some
>>point: how much faster is it in practice to pass/return 13 values in
>>registers instead of 8 of them in registers and the remaining 5 on
>>the stack?  I expect a 13-arg function to perform an amount
>>of work that will dwarf the extra work of going through the stack.
> I certainly have a use for as many arguments as the ABI provides,

Ah, yes, machine-generated code can always defy intuitions about what
is "typical".  🙂


        Stefan

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

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