Need help in figuring out the flow of RTEMS codes

[Richi Dubey]

This makes sense. Thanks a lot!


On Fri, May 29, 2020 at 1:18 PM Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
>
> Hello Richi,
>
> On 29/05/2020 09:36, Richi Dubey wrote:
> > Hii,
> >
> > I had a small doubt about all the source code/procedures that a code
> > goes through. Where can I read more about it? For instance, when I am
> > debugging smpschededf02.exe with gdb, It starts  with
> > bsps/sparc/shared/start/start.S, line 107(Why did it start with
> > start.s?) and the last line of this file is:
> >
> >   mov     %g0, %o0                ! command line
> >          call    SYM(boot_card)          ! does not return
> >           sub     %sp, 0x60, %sp         ! room for boot_card to save args
> >
> > After this it starts executing bsps/shared/start/bootcard.c: line 53 .
> > How did this happen? Is it because of call? If yes, why was sub
> > executed(in gdb) before executing code from bootcard.c?
> >
> > I hope I am not trying to going too deep into this. I just want to
> > have a overall picture of how a code gets executed.
>
> if you want to learn how code executes at processor level, then I would
> recommend to work with an ARM (Qemu) or RISC-V (SIS, Qemu) simulator.
> These are the currently most relevant architectures. SPARC is a dead
> architecture and it has some peculiarities which were a nice idea in the
> 1980s.
>
> > This is necessary
> > for writing your own code in RTEMS, right?
> It helps, but it is not necessary.