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

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In article <5c2f5bb58bNews03@avisoft.f9.co.uk>,
   Martin <News03@avisoft.f9.co.uk> wrote:
> 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)

Pardon, I meant the file type "absolute". It is not always so easy to
work here in the "shelter" for the homeless. It is very public here. I
was disturbed very often.

http://home.chiemgau-net.de/ausserstorfer/Temp/2025-06-20/Absolute.jpg (60
kB)

> [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.

Thanks. Let do that task RISC OS means doing it by software. Isn't that
a brake for the performance?

It would also be good to know how this works under Android, for example.
I have a Gemini-PDA which runs this OS. And which editor could be used
there.

> [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

Thanks. Web is very expensive. I cannot be often and long en ligne.
Also, most of the web pages today just won't work anymore. I have to go
to elsewhere to get them correct on the screen. It is very complicated
to work this way. It is better to have the information bundled on the
machine.

The web today is very inefficient when you count the amount of data and
the result (what you need or want to know).

What about the programm counter? Was there any changes to it since the
release of the PRMs for RISC OS 3?

> 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.

Pardon, I don't understand that. Changes should be documented and
published always on the fly. I often read about the issue of 26 bit code
and 32 bit code in the GAG news for example. But there was never an
explanation of that. The articles there are always just on the face of
it.

A.

-- 
http://home.chiemgau-net.de/ausserstorfer/

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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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