Re: [ECOS] RE : Bug in CtrlC handling when sharing Ethernet btw Redboot/eCos

[Bart Veer <bartv at ecoscentric dot com>]

>>>>> "Arnaud" == Arnaud Chataignier <achataignier@neotion.com> writes:

    Arnaud> Dear Bart,
    Arnaud> Thank you for your answer on this topic. I agree with your
    Arnaud> conclusions.

    <snip>

    Arnaud> 2 - as you say, we can also clear
    Arnaud> hal_saved_interrupt_state before in
    Arnaud> eth_drv_run_deliveries() before calling HAL_CTRLC_CHECK.
    Arnaud> This will lead to always break execution in
    Arnaud> eth_drv_run_deliveries(), but the user can still see the
    Arnaud> state of other threads by using the 'thread awareness'
    Arnaud> functionnality of GDB/stubs. Note that just clearing the
    Arnaud> variable hal_saved_interrupt_state in
    Arnaud> eth_drv_run_deliveries() is not enough, since a new
    Arnaud> interrupt (timer for instance) can occur between the
    Arnaud> variable clearance, and the call to
    Arnaud> cyg_hal_user_break()(). But I know how to overcome this
    Arnaud> problem by using a global variable (the ugly solution I
    Arnaud> described below).

That is not exactly what I suggested. Instead a better place to clear
hal_saved_interrupt_state would be in the kernel's interrupt_end()
routine, which gets invoked at the end of a interrupt processing.
Probably just before the Cyg_Scheduler::unlock() call.

When debugging over serial there should be no difference in behaviour,
the ctrl-C detection happens in the ISR so hal_saved_interrupt_state
will be defined.

When debugging over ethernet, inside eth_drv_run_deliveries(),
hal_saved_interrupt_state will be clear. There is no need to worry
about other interrupts, these may briefly cause
hal_saved_interrupt_state to become set but the variable will be
cleared again before the thread resumes.

This should eliminate the need for an extra global, or an extra
argument to HAL_CTRLC_CHECK(), or anything similar.

Bart

-- 
Bart Veer                       eCos Configuration Architect
http://www.ecoscentric.com/     The eCos and RedBoot experts

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