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Re: File type of machine code? Where does it start?

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I have replied to some of your points...

In article <5c2f4363e6bavariasound@chiemgau-net.de>,
   Alexander Ausserstorfer <bavariasound@chiemgau-net.de> wrote:
> I created a new file in !StrongEd and saved it with file type
> "application". 

There is no filetype for 'Application', so not sure what you mean
here. Application is a special name given to a directory (not a file)
that starts with a ! (an exclamation mark, commonly referred to as a
pling in this context)

[Snip]

> An application will always be loaded and started by RISC OS on
> address &08000. This is a bit strange because RISC OS can hold
> different applications at the same time in the RAM. Normally, the
> programs would be overwritten when all are loaded at the same
> location of memory. But between the ARM and the RAM you have the
> MEMC (this I grab from the PRMs 3 - is that still the case today?).
> The MEMC maps the memory for the applications and moves it to
> elsewhere, to a place where is free memory.

Applications do always appear to start at &8000, but this is just a
'virtual' address. It will actually be at a physical real address, and
the translation is done for you by RISC OS so you always deal with the
virtual addresses. There is no longer a MEMC chip involved. 

[Snip]

> It seems to me that there are existing much
> different ARM chips today. What are the differences? Which ones are
> relevant for RISC OS today? I'm have some Raspberry Pi's and an
> Elesar's Titanium. Never read about this issue.

There is lots on the web, but probably best place to start is
https://www.riscosopen.org

Click on Library, go down to Programmer Documentation and click on the
Programmer Documentation link, then click on ARMV6+ compatibility
primer. You should end up at
https://www.riscosopen.org/wiki/documentation/show/ARMv7%20compatibility%20primer
but it gives you an idea of other things available on this one site.

> I'm also a bit confused about the documentation. I have the
> Programmer's Reference Manuals here. But they are for RISC OS 3.
> What was chanced in meantime, what is still valid from them today?

Most of it is still valid with RO5, apart from the 26bit to 32bit
changes. An updated version of the PRMs is being worked on ... but it
is a mammoth project.  If you click on Bounties at the top of the ROOL
page, you will see details of the work for Revide PRMs step 1.

Some updates since RO3 are available in the ROOL Library, and the
Style Guide, BASIC and DDE manuals have all been updated.

-- 
Martin Avison 
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received. 

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Thread

File type of machine code? Where does it start? Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-07 17:41 +0200
  Re: File type of machine code? Where does it start? Martin <News03@avisoft.f9.co.uk> - 2025-06-07 18:14 +0100
    Re: File type of machine code? Where does it start? Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-08 18:26 +0200
  Re: File type of machine code? Where does it start? Theo <theom+news@chiark.greenend.org.uk> - 2025-06-08 11:02 +0100
    Re: File type of machine code? Where does it start? Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-08 18:32 +0200
      Re: File type of machine code? Where does it start? Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-19 07:22 +0200
        Re: File type of machine code? Where does it start? Jean-Michel <jmc.bruck@orange.fr> - 2025-06-19 11:23 +0200
          Re: File type of machine code? Where does it start? druck <news@druck.org.uk> - 2025-06-24 20:47 +0100
            Re: File type of machine code? Where does it start? Bob Latham <bob@sick-of-spam.invalid> - 2025-06-25 09:29 +0100
        Re: File type of machine code? Where does it start? Martin <News03@avisoft.f9.co.uk> - 2025-06-19 10:48 +0100
          Re: File type of machine code? Where does it start? Alexander Ausserstorfer <bavariasound@chiemgau-net.de> - 2025-06-20 17:22 +0200
            Re: File type of machine code? Where does it start? Matthew Phillips <spam2011m@yahoo.co.uk> - 2025-06-21 08:20 +0100
        Re: File type of machine code? Where does it start? Theo <theom+news@chiark.greenend.org.uk> - 2025-06-20 17:25 +0100

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