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Re: Questions about the Implementation of the ELF format

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On Thu, 26 May 2016 14:51:42 -0700 (PDT)
"Isaac D. Cohen" <8switchsoftware@gmail.com> wrote:

> So how can we create a pure binary kernel?

A more important question might be, "Why do you want one?" ...

You generally need a pure binary for a bootable code such as a
bootloader, but usually not much else.  A bootloader will usually only
start an OS image that is _NOT_ a pure binary.  Bootloaders will start
execution of an OS image which has a specific executable or object
format or a special header, such as ELF, or DOS OMF, or COFF, or
whatever M$ uses, or that which has a Multiboot header, etc.

If you've coded your own bootloader, then you just need to call or jump
to the entry point in your executable image, e.g., to main() for C or a
"start" label for assembly.  Usually, C compilers include some assembly
labels which are accessible, such as some variation of "start".
However, if the compiler or assembler produces an executable format,
such as ELF, COFF, PE, etc, then the executable header provides an
entry point to start execution.  I.e., this has been done for you, if
your bootloader can obtain information from the executable header.

You definitely need to make sure the kernel is not dependent on
any system libraries, e.g., static code, or not doesn't use them.  This
usually requires some compiler specific flags to warn or error if you
do.

Of course, you can, if careful, use some system code since some of it
won't be dependent on the host OS.  These will be very basic functions.


Rod Pemberton

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Thread

Questions about the Implementation of the ELF format "Isaac D. Cohen" <8switchsoftware@gmail.com> - 2016-05-23 22:07 -0700
  Re: Questions about the Implementation of the ELF format Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-05-24 03:48 -0400
  Questions about the Implementation of the ELF format Peter Cheung <mcheung63@gmail.com> - 2016-05-24 01:10 -0700
  Re: Questions about the Implementation of the ELF format "Alexei A. Frounze" <alexfrunews@gmail.com> - 2016-05-24 01:18 -0700
  Re: Questions about the Implementation of the ELF format "Mike Gonta" <mikegonta@gmail.com> - 2016-05-24 10:34 -0400
  Re: Questions about the Implementation of the ELF format Herbert Kleebauer <klee@unibwm.de> - 2016-05-24 17:24 +0200
  Re: Questions about the Implementation of the ELF format "Isaac D. Cohen" <8switchsoftware@gmail.com> - 2016-05-24 14:18 -0700
    Re: Questions about the Implementation of the ELF format "Alexei A. Frounze" <alexfrunews@gmail.com> - 2016-05-25 02:21 -0700
  Re: Questions about the Implementation of the ELF format "Isaac D. Cohen" <8switchsoftware@gmail.com> - 2016-05-25 15:02 -0700
    Re: Questions about the Implementation of the ELF format "Mike Gonta" <mikegonta@gmail.com> - 2016-05-25 19:03 -0400
      Re: Questions about the Implementation of the ELF format "Isaac D. Cohen" <8switchsoftware@gmail.com> - 2016-05-26 14:51 -0700
        Re: Questions about the Implementation of the ELF format Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-05-27 02:55 -0400
          Re: Questions about the Implementation of the ELF format "Isaac D. Cohen" <8switchsoftware@gmail.com> - 2016-05-27 13:43 -0700
            Re: Questions about the Implementation of the ELF format "Mike Gonta" <mikegonta@gmail.com> - 2016-05-27 17:40 -0400
              Re: Questions about the Implementation of the ELF format "Isaac D. Cohen" <8switchsoftware@gmail.com> - 2016-05-28 20:15 -0700
                Re: Questions about the Implementation of the ELF format Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-05-29 02:35 -0400
                Re: Questions about the Implementation of the ELF format "Isaac D. Cohen" <8switchsoftware@gmail.com> - 2016-06-15 13:51 -0700
        Re: Questions about the Implementation of the ELF format Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-05-27 03:09 -0400
        Re: Questions about the Implementation of the ELF format "Alexei A. Frounze" <alexfrunews@gmail.com> - 2016-05-27 00:10 -0700
        Re: Questions about the Implementation of the ELF format Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-06-02 16:25 -0400
      Re: Questions about the Implementation of the ELF format Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-05-27 02:38 -0400
        Re: Questions about the Implementation of the ELF format "Mike Gonta" <mikegonta@gmail.com> - 2016-05-27 04:11 -0400
    Re: Questions about the Implementation of the ELF format "Alexei A. Frounze" <alexfrunews@gmail.com> - 2016-05-25 22:18 -0700

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