Re: Learning ARM machine code

From	Steve Fryatt <news@stevefryatt.org.uk>
Newsgroups	comp.sys.acorn.programmer
Subject	Re: Learning ARM machine code
Date	2025-11-15 23:46 +0000
Organization	A noiseless patient Spider
Message-ID	<mpro.t5skpi00iwsze149i.news@stevefryatt.org.uk> (permalink)
References	(4 earlier) <iKm*CnCeA@news.chiark.greenend.org.uk> <5c2adc4465bavariasound@chiemgau-net.de> <5c2cea6fccbavariasound@chiemgau-net.de> <5c75805cc6bavariasound@chiemgau-net.de> <5c7c29dce9bavariasound@chiemgau-net.de>

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On 15 Nov, Alexander Ausserstorfer wrote in message
    <5c7c29dce9bavariasound@chiemgau-net.de>:

> And if I use the GCC to convert the command MOV PC, R14 to machine code,
> the result is not a file type of Absolute but of ELF and it has a file
> size of huge blowy shit! 784 bytes for just ONE command! I don't
> understand that.

Because an ELF file isn't just the code itself: it's a structured file that
can contain more data. So somewhere in there will be the 4 bytes of the MOV
command, plus a header to tell the ELF loader where in memory to put that
command when it loads the file. And other infrastructure needed to allow the
file to do things like initialise separate blocks of memory, or load other
chunks of assembled commands, linkable blocks like libraries, and so on.

We moved on from doing *Save and *Load many years ago, because it's not that
flexible and forces too many assumptions about the file contents to be made.

See https://en.wikipedia.org/wiki/Executable_and_Linkable_Format for
details.

-- 
Steve Fryatt - Leeds, England

http://www.stevefryatt.org.uk/

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Thread

Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-04-12 15:11 +0200
  Re: Learning ARM machine code Harriet Bazley <harriet@bazleyfamily.co.uk> - 2025-04-13 18:27 +0100
    Re: Learning ARM machine code Jean-Michel <jmc.bruck@orange.fr> - 2025-04-14 11:40 +0200
  Re: Learning ARM machine code Theo <theom+news@chiark.greenend.org.uk> - 2025-04-14 17:56 +0100
    Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-07 17:08 +0200
      Re: Learning ARM machine code Sebastian Barthel <naitsabes@freenet.de> - 2025-06-09 13:04 +0000
        Re: Learning ARM machine code Theo <theom+news@chiark.greenend.org.uk> - 2025-06-09 17:36 +0100
          Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-10 18:11 +0200
            Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-14 17:58 +0200
              Re: Learning ARM machine code Martin <News03@avisoft.f9.co.uk> - 2025-06-14 17:54 +0100
                Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-19 06:31 +0200
                Re: Learning ARM machine code Martin <News03@avisoft.f9.co.uk> - 2025-06-19 10:09 +0100
                Re: Learning ARM machine code Jean-Michel <jmc.bruck@orange.fr> - 2025-06-19 11:32 +0200
              Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-11-02 16:42 +0200
                Re: Learning ARM machine code Martin <News03@avisoft.f9.co.uk> - 2025-11-02 17:01 +0000
                Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-11-15 14:55 +0200
                Re: Learning ARM machine code druck <news@druck.org.uk> - 2025-11-17 19:08 +0000
                Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-11-15 15:11 +0200
                Re: Learning ARM machine code Harriet Bazley <harriet@bazleyfamily.co.uk> - 2025-11-15 19:46 +0000
                Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-12-06 17:57 +0200
                Re: Learning ARM machine code Martin <News04@avisoft.f9.co.uk> - 2025-12-06 18:15 +0000
                Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-12-07 16:25 +0200
                Re: Learning ARM machine code Martin <News04@avisoft.f9.co.uk> - 2025-12-07 15:57 +0000
                Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-12-21 17:13 +0200
                Re: Learning ARM machine code druck <news@druck.org.uk> - 2025-12-22 20:02 +0000
                Re: Learning ARM machine code Paul Sprangers <Paul@sprie.nl> - 2025-12-22 23:32 +0100
                Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2026-01-06 14:42 +0200
                Re: Learning ARM machine code anonymouse <na@ignoreme.com> - 2026-01-06 15:02 +0000
                Re: Learning ARM machine code Jean-Michel <jmc.bruck@orange.fr> - 2025-12-08 10:23 +0100
                Re: Learning ARM machine code Harriet Bazley <harriet@bazleyfamily.co.uk> - 2025-12-06 20:06 +0000
                Re: Learning ARM machine code druck <news@druck.org.uk> - 2025-12-09 08:21 +0000
                Re: Learning ARM machine code Martin <News04@avisoft.f9.co.uk> - 2025-12-09 09:48 +0000
                Re: Learning ARM machine code Richard Ashbery <basura@invalid.addr.uk> - 2025-12-09 10:54 +0000
                Re: Learning ARM machine code Steve Fryatt <news@stevefryatt.org.uk> - 2025-11-15 23:46 +0000
                Re: Learning ARM machine code Theo <theom+news@chiark.greenend.org.uk> - 2025-11-16 11:59 +0000
                Re: Learning ARM machine code Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-12-06 18:10 +0200
                Re: Learning ARM machine code Steve Fryatt <news@stevefryatt.org.uk> - 2025-12-07 12:18 +0000
          Re: Learning ARM machine code Sebastian Barthel <naitsabes@freenet.de> - 2025-06-10 18:37 +0000

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