[U-Boot-Users] booting elf image?

[Wolfgang Denk]

[Please keep the list on cc:]

In message <8bf247760608010750n4da0cde9u376a2b521ed05187 at mail.gmail.com> you wrote:
>
> That is the reason i have built executable which is statically linked.
> 
> isnt this enough?.

No, of course not.

As I wrote in my first reply, you need at least a basic understanding
of the operating system, of the system services provided by an OS, of
the libraries that are based on these services, and of  the  run-time
environments for C programs.

In your code you use the printf() function - guess what it  does?  It
will  boil  down to using some system calls - like write(). This is a
service provided by your OS. Also it relies on concepts like standard
I/O streams (namely, stdout), which in turn relies  on  the  standard
file  descriptors  0,  1,  and  2  being set up by your OS. The whole
concept of a "process" and it's environment (virtual  address  space,
open file descriptors, etc.) is highly OS dependent.

Do you think another OS (say, Windoze) would provide exactly teh same
(binary compatible!) system call interface? Or process environment?

And do you really think  a  simple  boot  loader  like  U-Boot  would
provide such services?


Well, let me tell you: it ain't so.

Your a.out program will only run in a Linux environment  (or  in  one
which  is  compatible  -  for  example,  it  is possible to run Linux
binaries under FreeBSD).


Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Nothing ever becomes real until it is experienced.       - John Keats