Semaphore

Classes
class	semaphore

Functions
	semaphore::semaphore ()
	semaphore::semaphore (int16_t initial_value)
void	semaphore::init (void)
void	semaphore::post (void)
void	semaphore::wait (void)
void	semaphore::take (void)
bool	semaphore::guard (void)
bool	semaphore::blocked (void)
void	semaphore::reset (void)

Variables
int16_t	semaphore::value
uint32_t	semaphore::total_posts

Detailed Description

Function Documentation

bool semaphore::blocked

(

void

)

True if the semaphore is blocked.

Definition at line 68 of file semaphorepp.cpp.

References value.

Referenced by wait().

                        {

    return value <= 0;
}

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bool semaphore::guard

(

void

)

without the waiting – take if ready, leave if not.

Warning

this decrements the semaphore if the return value is true.

Definition at line 57 of file semaphorepp.cpp.

References critical::EndCritical(), critical::StartCritical(), and value.

Referenced by can_handler(), motor_control(), ping_handler(), shell_handler(), switch_responder(), thread_blink_blue(), thread_blink_green(), and thread_blink_red().

                      {

    uint32_t status = StartCritical();
    bool ret = value > 0;
    if (ret) {
        --value;
    }
    EndCritical(status);
    return ret;
}

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void semaphore::init

(

void

)

Definition at line 21 of file semaphorepp.cpp.

References total_posts.

Referenced by semaphore().

                     {

#if TEST_SEMAPHORE == 1
    total_posts = 0;
#endif
}

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void semaphore::post

(

void

)

Increment the semaphore.

Definition at line 45 of file semaphorepp.cpp.

References critical::EndCritical(), critical::StartCritical(), total_posts, and value.

Referenced by CAN0_Handler(), lswitch::end_debounce(), ping::handle_timer(), shell::motor_start(), shell::motor_stop(), buffer< int32_t, N >::notify(), and ping::start().

                     {

    int32_t status = StartCritical();
    ++value;
#if TEST_SEMAPHORE == 1
    ++total_posts;
#endif
    EndCritical(status);
}

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void semaphore::reset

(

void

)

Reset the semaphore.

Definition at line 28 of file semaphorepp.cpp.

References critical::EndCritical(), critical::StartCritical(), and value.

Referenced by semaphore(), and ping::stop().

                      {

    int32_t status = StartCritical();
    value = 0;
    EndCritical(status);
}

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semaphore::semaphore

(

)

Definition at line 7 of file semaphorepp.cpp.

References init(), and reset().

                     {

    init();
    reset();
}

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semaphore::semaphore

(

int16_t

initial_value

)

Definition at line 13 of file semaphorepp.cpp.

References critical::EndCritical(), init(), critical::StartCritical(), and value.

                                          {

    int32_t status = StartCritical();
    value = initial_value;
    EndCritical(status);
    init();
}

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void semaphore::take

(

void

)

Take the semaphore

void semaphore::wait

(

void

)

Wait on a semaphore.

Definition at line 35 of file semaphorepp.cpp.

References blocked(), critical::EndCritical(), critical::StartCritical(), and value.

                     {

    while(blocked()) {
        os_surrender_context();
    }
    int32_t status = StartCritical();
    --value;
    EndCritical(status);
}

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Variable Documentation

uint32_t semaphore::total_posts

private

Definition at line 21 of file semaphorepp.hpp.

Referenced by init(), and post().

int16_t semaphore::value

private

Definition at line 19 of file semaphorepp.hpp.

Referenced by blocked(), guard(), post(), reset(), semaphore(), and wait().