[ECOS] GDB and eCos

[ECOS] GDB and eCos

[andre33]

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    Hello,
    So i'm a newbie

    It seem that GDB can emulate the target !! i'm wrong ?

   So my idea for begining is try to load eCos kernel + hello
application in GDB (emulator mode) without real    target if it's
possible !  for see what is happened !!

    But if it's possible where i need to start !!??
    i have arm-elf-gcc , arm-elf-gdb et eCos builded

    How can i load eCos kernel and the hello application ? and after run
it !

    best regards,

Sébastien.

Re: [ECOS] GDB and eCos

[Bart Veer]

>>>>> "Sebastien" == andre33  <sebastien.andre@sxb.bsf.alcatel.fr> writes:

    Sebastien>     Hello,
    Sebastien>     So i'm a newbie

    Sebastien>     It seem that GDB can emulate the target !! i'm
    Sebastien>     wrong ?

Partly correct.

Typically when gcc is ported to a new architecture, one of the first
steps is to write an instruction set simulator for that architecture.
This allows the compiler folks to do their development and testing
before any hardware exists. It is also very useful for subsequent
maintenance. However, this is just an instruction set simulator. It
will do enough to support compiler testing. It will provide only
minimal I/O facilities which bear no resemblance to how I/O happens on
real hardware. Hence typically it cannot be used for eCos development.
The simulator gets built into gdb when you configure for the
appropriate target.

During the early days of eCos development, the simulators for two of
the initial targets (AM31 and TX39) were enhanced to support
architectural simulation of specific boards, the stdeval1 board and
the JMR-TX3904 board. This architectural simulation included support
for a system clock, serial I/O, and interrupt handling, but not for
anything more advanced like ethernet or PCI. In addition eCos was
ported to the PowerPC psim simulator. More details of these can be
found at http://sources.redhat.com/ecos/hardware.html and in the
Getting Started guides for those targets.

More recent work on architectural simulators within Red Hat has
happened in the context of the SID project, http://sources.redhat.com/sid/
Unfortunately I do not really have time to track that project closely
but I suggest you take a look through their web pages and
documentation.

Bart

Re: [ECOS] GDB and eCos

[andre33]

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Hello,

Thanx for you answer !! so maybe i must start directly with the target
but i'm afraid to be losing with the bootstrap (boot, register init, etc ..)
for beginning :-(
So i will see !!

Thanx again and i will see links you say !!!

best regards,
Sébastien.



Bart Veer wrote:

> >>>>> "Sebastien" == andre33  <sebastien.andre@sxb.bsf.alcatel.fr> writes:
>
>     Sebastien>     Hello,
>     Sebastien>     So i'm a newbie
>
>     Sebastien>     It seem that GDB can emulate the target !! i'm
>     Sebastien>     wrong ?
>
> Partly correct.
>
> Typically when gcc is ported to a new architecture, one of the first
> steps is to write an instruction set simulator for that architecture.
> This allows the compiler folks to do their development and testing
> before any hardware exists. It is also very useful for subsequent
> maintenance. However, this is just an instruction set simulator. It
> will do enough to support compiler testing. It will provide only
> minimal I/O facilities which bear no resemblance to how I/O happens on
> real hardware. Hence typically it cannot be used for eCos development.
> The simulator gets built into gdb when you configure for the
> appropriate target.
>
> During the early days of eCos development, the simulators for two of
> the initial targets (AM31 and TX39) were enhanced to support
> architectural simulation of specific boards, the stdeval1 board and
> the JMR-TX3904 board. This architectural simulation included support
> for a system clock, serial I/O, and interrupt handling, but not for
> anything more advanced like ethernet or PCI. In addition eCos was
> ported to the PowerPC psim simulator. More details of these can be
> found at http://sources.redhat.com/ecos/hardware.html and in the
> Getting Started guides for those targets.
>
> More recent work on architectural simulators within Red Hat has
> happened in the context of the SID project, http://sources.redhat.com/sid/
> Unfortunately I do not really have time to track that project closely
> but I suggest you take a look through their web pages and
> documentation.
>
> Bart

[ECOS] cyg_semaphore_post

[Joerg Rapka]

Hi

Is it allowed to call cyg_semaphore_post from within an ISR?

Thanks,
Joerg

Re: [ECOS] cyg_semaphore_post

[Bart Veer]

>>>>> "Joerg" == Joerg Rapka <joerg.rapka@duagon.com> writes:

    Joerg> Is it allowed to call cyg_semaphore_post from within an
    Joerg> ISR?

No. In general it is not possible to call any kernel function from
inside an ISR because kernel operations like manipulating a semaphore
only lock the scheduler, they do not disable interrupts. This helps to
keep down the interrupt latency. Instead the ISR should indicate that
its corresponding DSR should be run, using its return value. The DSR
will be run when it is safe to do so. Usually this will be
immediately, but if the interrupted code was in a critical section and
had locked the scheduler then the DSR will be run a little bit later
when the critical section has been exited. The DSR can make
non-blocking calls such as cyg_semaphore_post()

For more information, see e.g. the section "eCos Interrupt Model" in
the Reference Guide.

Bart