Watch Class Reference

The Watch device deals with timer interrupts. More...

#include <device/watch.h>

Inheritance diagram for Watch:

Collaboration diagram for Watch:

Public Member Functions
	Watch ()
bool	windup (uint32_t us)
	Windup / initialize.
bool	prologue () override
	Prologue of timer interrupts.
void	epilogue () override
	Epilogue of timer interrupts.
uint32_t	interval () const
	Retrieve the interrupt interval.
void	activate () const
	Activate the timer on this core.
Public Member Functions inherited from Gate
	Gate ()
	Constructor.
virtual	~Gate ()
	Destructor.
bool	is_queued () const
	Status about the epilogue.
void	set_queued (bool val)
	Set epilogue status.

Static Public Member Functions
static void	block ()
	Blocks the timer interrupts on this core.
static void	unblock ()
	Allow the previously blocked timer interrupts on this core.

Private Member Functions
	Watch (const Watch &)=delete
Watch &	operator= (const Watch &)=delete

Private Attributes
uint32_t	interv
uint32_t	ticks
uint32_t	div

Additional Inherited Members
Protected Member Functions inherited from Queue< T, ContainerType >::Node
	Node ()

Detailed Description

The Watch device deals with timer interrupts.

Handles LAPIC::Timer interrupts, therefore managing the time slices and triggering a thread switch if necessary.

Constructor & Destructor Documentation

Watch() [1/2]

Watch::Watch ( const Watch &  )

privatedelete

Watch() [2/2]

Watch::Watch ( )

inline

Member Function Documentation

operator=()

Watch & Watch::operator= ( const Watch &  )

privatedelete

windup()

bool Watch::windup

(

uint32_t

us

)

Windup / initialize.

Assigns itself to the Plugbox and initializes the LAPIC::Timer in such a way that regular interrupts are triggered approx. every us microseconds. However, the LAPIC::Timer is not armed until Watch::activate() is called. Hence, Watch::windup() just sets up all the values. For this purpose, a suitable timer divisor is determined based on the timer frequency determined with LAPIC::Timer::ticks(). This timer divisor has to be as small as possible, but large enough to prevent the 32bit counter from overflowing.

Parameters

us	Desired interrupt interval in microseconds.

Returns

Indicates if the interval could be set.

prologue()

bool Watch::prologue ( )

overridevirtual

Prologue of timer interrupts.

Returns

true if the Watch::epilogue should be executed.

Implements Gate.

epilogue()

void Watch::epilogue ( )

overridevirtual

Epilogue of timer interrupts.

Triggers the thread switch and checks the Bellringer.

Todo:

Extend method (add Bellringer)

Reimplemented from Gate.

interval()

uint32_t Watch::interval

(

)

const

Retrieve the interrupt interval.

Returns

Interval in microseconds

activate()

void Watch::activate

(

)

const

Activate the timer on this core.

Activate the LAPIC::Timer using LAPIC::Timer::set(). The core local timer starts with the interval previously configured in windup(). To get timer interrupts on all cores, this method must be called once per core (however, it is sufficient to call windup only once since the APIC-Bus frequency is the same on each core).

block()

void Watch::block ( )

static

Blocks the timer interrupts on this core.

The LAPIC Timer can be masked with LAPIC::Timer::setMasked as soon as no thread is ready and no Bell is waiting to be counted down. block() and unblock() must be called from the idle loop.

Optional:

Implement for tickless kernel

unblock()

void Watch::unblock ( )

static

Allow the previously blocked timer interrupts on this core.

Logical counterpart to Watch::block(). Allows the delivery of core local timer interrupts again.

Optional:

Implement for tickless kernel

Member Data Documentation

interv

uint32_t Watch::interv

private

ticks

uint32_t Watch::ticks

private

div

uint32_t Watch::div

private

---

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

• device/watch.h
• device/watch.cc