QP::QK Class Reference

QK preemptive non-blocking kernel. More...

#include <qk.hpp>

Static Public Member Functions
static QSchedStatus	schedLock (std::uint8_t const ceiling) noexcept
	QK selective scheduler lock.
static void	schedUnlock (QSchedStatus const prevCeil) noexcept
	QK selective scheduler unlock.
static void	onIdle ()
	QK idle callback (customized in BSPs for QK).
static std::uint_fast8_t	sched_ () noexcept
	QK scheduler finds the highest-priority AO ready to run.
static std::uint_fast8_t	sched_act_ (QActive const *const act, std::uint_fast8_t const pthre_in) noexcept
	QK internal helper function to determine whether activation is needed.
static void	activate_ ()
	QK activator activates the next active object. The activated AO preempts the currently executing AOs.

Public Attributes
QP::QPSet	readySet
	Set of active-objects/threads that are ready to run in the QK kernel.
std::uint8_t	actPrio
	Priority of the currently active AO.
std::uint8_t	nextPrio
	Next AO priority scheduled by QK.
std::uint8_t	actThre
	Preemption threshold of the currently active AO.
std::uint8_t	lockCeil
	Scheduler lock-ceiling (0 if scheduler unlocked).
std::uint8_t	intNest
	Up-down counter indicating current interrupt nesting (used in some QK ports).

Static Public Attributes
static QK	priv_

Detailed Description

QK preemptive non-blocking kernel.

See also

Preemptive Non-Blocking Kernel

Definition at line 38 of file qk.hpp.

Member Function Documentation

schedLock()

QSchedStatus QP::QK::schedLock ( std::uint8_t const ceiling )

staticnoexcept

QK selective scheduler lock.

Details
This function locks the QK scheduler to the specified ceiling.

Parameters

[in]

ceiling

preemption ceiling to which the QK scheduler needs to be locked

Returns

The previous QK Scheduler lock status, which is to be used to unlock the scheduler by restoring its previous lock status in QK::schedUnlock().

Note

QK::schedLock() must be always followed by the corresponding QK_schedUnlock().

See also

QK_schedUnlock()

Usage
The following example shows how to lock and unlock the QK scheduler:

std::uint32_t BSP::random() {
    std::uint32_rnd;
 
    QSchedStatus lockStat = QK::schedLock(N_PHILO); // <== N_PHILO ceiling
    . . . // access/manipulate the shared random seed resource
    QK::schedUnlock(lockStat); // <=== unlock
 
    return rnd;
}

Definition at line 56 of file qk.cpp.

schedUnlock()

void QP::QK::schedUnlock ( QSchedStatus const prevCeil )

staticnoexcept

QK selective scheduler unlock.

Details
This function unlocks the QK scheduler to the previous status.

Parameters

[in]

prevCeil

previous QK Scheduler lock ceiling returned from QK::schedLock()

Note

QK::schedUnlock() must always follow the corresponding QK::schedLock().

See also

QK::schedLock()

Usage
The following example shows how to lock and unlock the QK scheduler:

std::uint32_t BSP::random() {
    std::uint32_rnd;
 
    QP::QSchedStatus lockStat = QK::schedLock(N_PHILO); // <== N_PHILO ceiling
    . . . // access/manipulate the shared random seed resource
    QK::schedUnlock(lockStat); // <=== unlock
 
    return rnd;
}

Definition at line 83 of file qk.cpp.

onIdle()

void QP::QK::onIdle ( )

static

QK idle callback (customized in BSPs for QK).

Details
QK::onIdle() is called continuously by the QK idle loop. This callback gives the application an opportunity to enter a power-saving CPU mode, or perform some other idle processing.

Note

QK::onIdle() is invoked with interrupts enabled and must also return with interrupts enabled.

sched_()

std::uint_fast8_t QP::QK::sched_ ( )

staticnoexcept

QK scheduler finds the highest-priority AO ready to run.

Details
The QK scheduler finds out the priority of the highest-priority AO that (1) has events to process and (2) has priority that is above the current priority.

Returns

The QF-priority of the next Active Object to activate, or zero if no activation of AO is needed.

Attention

QK::sched_() must be always called with interrupts disabled and returns with interrupts disabled.

Definition at line 115 of file qk.cpp.

sched_act_()

std::uint_fast8_t QP::QK::sched_act_ ( QActive const *const act, std::uint_fast8_t const pthre_in )

staticnoexcept

QK internal helper function to determine whether activation is needed.

Details

Parameters

[in]	act	currently executing Active Object
[in]	pthre_in	current priority threshold

Returns

the priority of Active Object to activate or 0 if no activation needed

Attention

QK::act_() must be always called with interrupts disabled and returns with interrupts disabled.

Definition at line 142 of file qk.cpp.

activate_()

void QP::QK::activate_ ( )

static

QK activator activates the next active object. The activated AO preempts the currently executing AOs.

Details
QK::activate_() activates ready-to run AOs that are above the initial preemption-threshold.

Attention

QK::activate_() must be always called with interrupts disabled and returns with interrupts disabled.

Definition at line 177 of file qk.cpp.

Member Data Documentation

readySet

QP::QPSet QP::QK::readySet

Set of active-objects/threads that are ready to run in the QK kernel.

Definition at line 40 of file qk.hpp.

actPrio

std::uint8_t QP::QK::actPrio

Priority of the currently active AO.

Definition at line 41 of file qk.hpp.

nextPrio

std::uint8_t QP::QK::nextPrio

Next AO priority scheduled by QK.

Definition at line 42 of file qk.hpp.

actThre

std::uint8_t QP::QK::actThre

Preemption threshold of the currently active AO.

Definition at line 43 of file qk.hpp.

lockCeil

std::uint8_t QP::QK::lockCeil

Scheduler lock-ceiling (0 if scheduler unlocked).

Definition at line 44 of file qk.hpp.

intNest

std::uint8_t QP::QK::intNest

Up-down counter indicating current interrupt nesting (used in some QK ports).

Definition at line 45 of file qk.hpp.

priv_

QK QP::QK::priv_

static

Definition at line 58 of file qk.hpp.

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The documentation for this class was generated from the following files:

• qk.hpp
• qk.cpp
• qk.dox