dxd::clock Class Reference

kernel-mode periodic software clock, mirroring dx::clock's tick()/run()/halt() shape More...

#include <dxd_clock.h>

Inheritance diagram for dxd::clock:

Collaboration diagram for dxd::clock:

Public Member Functions
virtual void	align (int64_t &)
	aligns the next objective(system time, 100ns units) to an external time base, e.g. a bus frame counter; the plain period by default
	clock ()
void	halt () noexcept
	stop and join the clock thread; no-op if never run()
os_result	run (int64_t period)
	create and start the clock thread(autonomous mode)
virtual void	tick ()=0
	per-tick handler, called from the clock's own thread at PASSIVE_LEVEL in autonomous mode, or synchronously by the owning device in pod mode.
virtual	~clock ()
	virtual destructur

Protected Types
enum class	priority { low = LOW_PRIORITY , realtime = LOW_REALTIME_PRIORITY , high = HIGH_PRIORITY }
	the thread priorities a driver's own thread is raised to More...

Protected Member Functions
void	join ()
	the completion event is signalled on launch()'s way out, the thread object only once the thread left the image; the thread itself never joins
os_result	prio (priority priority)
os_result	run ()

Static Protected Member Functions
static unsigned int	prio ()

Protected Attributes
os_result	status

Detailed Description

kernel-mode periodic software clock, mirroring dx::clock's tick()/run()/halt() shape

A dxd::process(PASSIVE_LEVEL system thread) that re-arms an absolute-due-time high resolution EX_TIMER after every tick() and waits for its expiry on the process's own event, so a derived class's tick() body runs without DISPATCH_LEVEL restrictions - unlike a DPC-driven timer. EX_TIMER_HIGH_RESOLUTION is what keeps the sub-millisecond period precision small buffer sizes need: a KTIMER expires on the system clock interrupt alone, 15.6 ms apart. Re-arming against an accumulated absolute due time each iteration avoids drift.

A device that never calls run() and instead calls tick() directly (from an externally-driven IOCTL, e.g. ioctl::stream::clock::frame) gets the pod/puppet mode - no thread, no timer, purely reactive; see dxd/CLAUDE.md's kernel clock notes. Both modes are this same class; the difference is only whether run() was ever called.

Member Enumeration Documentation

priority

enum class dxd::process::priority

stronginherited

the thread priorities a driver's own thread is raised to

Enumerator
low	Lowest thread priority level.
realtime	Lowest realtime priority level.
high	Highest thread priority level.

Constructor & Destructor Documentation

clock()

dxd::clock::clock ( )

inline

~clock()

virtual dxd::clock::~clock ( )

inlinevirtual

virtual destructur

clock base class needs virtual destructor; although its a dummy; to ensure inherited and composite objects to be correctly destructed.

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Member Function Documentation

align()

virtual void dxd::clock::align ( int64_t & )

inlinevirtual

aligns the next objective(system time, 100ns units) to an external time base, e.g. a bus frame counter; the plain period by default

halt()

void dxd::clock::halt ( )

inlinenoexcept

stop and join the clock thread; no-op if never run()

<wake launch()'s wait() so it observes running==false and exits

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join()

void dxd::process::join ( )

inlineprotectedinherited

the completion event is signalled on launch()'s way out, the thread object only once the thread left the image; the thread itself never joins

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prio() [1/2]

unsigned int dxd::process::prio ( )

inlinestaticinherited

prio() [2/2]

os_result dxd::process::prio ( priority priority )

inlineinherited

run() [1/2]

os_result dxd::clock::run ( int64_t period )

inline

create and start the clock thread(autonomous mode)

Parameters

period

tick period, 100ns units(see dxd::scale)

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run() [2/2]

os_result dxd::process::run ( )

inlineinherited

<no thread will: keeps ~process() from waiting forever

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tick()

virtual void dxd::clock::tick ( )

pure virtual

per-tick handler, called from the clock's own thread at PASSIVE_LEVEL in autonomous mode, or synchronously by the owning device in pod mode.

Member Data Documentation

status

os_result dxd::process::status

inherited

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

• dxd_clock.h