Provides synchronization locks. More...

#include <sys/lock.h>
#include <3ds/svc.h>

Data Structures
struct	LightEvent
	A light event. More...

struct	LightSemaphore
	A light semaphore. More...

Macros
#define	AtomicIncrement(ptr) __atomic_add_fetch((u32*)(ptr), 1, __ATOMIC_SEQ_CST)
	Performs an atomic pre-increment operation.

#define	AtomicDecrement(ptr) __atomic_sub_fetch((u32*)(ptr), 1, __ATOMIC_SEQ_CST)
	Performs an atomic pre-decrement operation.

#define	AtomicPostIncrement(ptr) __atomic_fetch_add((u32*)(ptr), 1, __ATOMIC_SEQ_CST)
	Performs an atomic post-increment operation.

#define	AtomicPostDecrement(ptr) __atomic_fetch_sub((u32*)(ptr), 1, __ATOMIC_SEQ_CST)
	Performs an atomic post-decrement operation.

#define	AtomicSwap(ptr, value) __atomic_exchange_n((u32*)(ptr), (value), __ATOMIC_SEQ_CST)
	Performs an atomic swap operation.

Typedefs
typedef _LOCK_T	LightLock
	A light lock.

typedef _LOCK_RECURSIVE_T	RecursiveLock
	A recursive lock.

typedef s32	CondVar
	A condition variable.

Functions
static void	__dsb (void)
	Performs a Data Synchronization Barrier operation.

static void	__dmb (void)
	Performs a Data Memory Barrier operation.

static void	__isb (void)
	Performs an Instruction Synchronization Barrier (officially "flush prefetch buffer") operation.

static void	__clrex (void)
	Performs a clrex operation.

static s32	__ldrex (s32 *addr)
	Performs a ldrex operation. More...

static bool	__strex (s32 *addr, s32 val)
	Performs a strex operation. More...

static u16	__ldrexh (u16 *addr)
	Performs a ldrexh operation. More...

static bool	__strexh (u16 *addr, u16 val)
	Performs a strexh operation. More...

static u8	__ldrexb (u8 *addr)
	Performs a ldrexb operation. More...

static bool	__strexb (u8 *addr, u8 val)
	Performs a strexb operation. More...

Result	syncArbitrateAddress (s32 *addr, ArbitrationType type, s32 value)
	Function used to implement user-mode synchronization primitives. More...

Result	syncArbitrateAddressWithTimeout (s32 *addr, ArbitrationType type, s32 value, s64 timeout_ns)
	Function used to implement user-mode synchronization primitives (with timeout). More...

void	LightLock_Init (LightLock *lock)
	Initializes a light lock. More...

void	LightLock_Lock (LightLock *lock)
	Locks a light lock. More...

int	LightLock_TryLock (LightLock *lock)
	Attempts to lock a light lock. More...

void	LightLock_Unlock (LightLock *lock)
	Unlocks a light lock. More...

void	RecursiveLock_Init (RecursiveLock *lock)
	Initializes a recursive lock. More...

void	RecursiveLock_Lock (RecursiveLock *lock)
	Locks a recursive lock. More...

int	RecursiveLock_TryLock (RecursiveLock *lock)
	Attempts to lock a recursive lock. More...

void	RecursiveLock_Unlock (RecursiveLock *lock)
	Unlocks a recursive lock. More...

void	CondVar_Init (CondVar *cv)
	Initializes a condition variable. More...

void	CondVar_Wait (CondVar cv, LightLock lock)
	Waits on a condition variable. More...

int	CondVar_WaitTimeout (CondVar cv, LightLock lock, s64 timeout_ns)
	Waits on a condition variable with a timeout. More...

void	CondVar_WakeUp (CondVar *cv, s32 num_threads)
	Wakes up threads waiting on a condition variable. More...

static void	CondVar_Signal (CondVar *cv)
	Wakes up a single thread waiting on a condition variable. More...

static void	CondVar_Broadcast (CondVar *cv)
	Wakes up all threads waiting on a condition variable. More...

void	LightEvent_Init (LightEvent *event, ResetType reset_type)
	Initializes a light event. More...

void	LightEvent_Clear (LightEvent *event)
	Clears a light event. More...

void	LightEvent_Pulse (LightEvent *event)
	Wakes up threads waiting on a sticky light event without signaling it. More...

void	LightEvent_Signal (LightEvent *event)
	Signals a light event, waking up threads waiting on it. More...

int	LightEvent_TryWait (LightEvent *event)
	Attempts to wait on a light event. More...

void	LightEvent_Wait (LightEvent *event)
	Waits on a light event. More...

int	LightEvent_WaitTimeout (LightEvent *event, s64 timeout_ns)
	Waits on a light event until either the event is signaled or the timeout is reached. More...

void	LightSemaphore_Init (LightSemaphore *semaphore, s16 initial_count, s16 max_count)
	Initializes a light semaphore. More...

void	LightSemaphore_Acquire (LightSemaphore *semaphore, s32 count)
	Acquires a light semaphore. More...

int	LightSemaphore_TryAcquire (LightSemaphore *semaphore, s32 count)
	Attempts to acquire a light semaphore. More...

void	LightSemaphore_Release (LightSemaphore *semaphore, s32 count)
	Releases a light semaphore. More...

Detailed Description

Provides synchronization locks.

Function Documentation

◆ __ldrex()

static s32 __ldrex ( s32 * addr )

inlinestatic

Performs a ldrex operation.

Parameters

addr	Address to perform the operation on.

Returns: The resulting value.

◆ __ldrexb()

static u8 __ldrexb ( u8 * addr )

inlinestatic

Performs a ldrexb operation.

Parameters

addr	Address to perform the operation on.

Returns: The resulting value.

◆ __ldrexh()

static u16 __ldrexh ( u16 * addr )

inlinestatic

Performs a ldrexh operation.

Parameters

addr	Address to perform the operation on.

Returns: The resulting value.

◆ __strex()

static bool __strex	(	s32 *	addr,
		s32	val
	)

inlinestatic

Performs a strex operation.

Parameters

addr	Address to perform the operation on.
val	Value to store.

Returns: Whether the operation was successful.

◆ __strexb()

static bool __strexb	(	u8 *	addr,
		u8	val
	)

inlinestatic

Performs a strexb operation.

Parameters

addr	Address to perform the operation on.
val	Value to store.

Returns: Whether the operation was successful.

◆ __strexh()

static bool __strexh	(	u16 *	addr,
		u16	val
	)

inlinestatic

Performs a strexh operation.

Parameters

addr	Address to perform the operation on.
val	Value to store.

Returns: Whether the operation was successful.

◆ CondVar_Broadcast()

static void CondVar_Broadcast ( CondVar * cv )

inlinestatic

Wakes up all threads waiting on a condition variable.

Parameters

cv	Pointer to the condition variable.

◆ CondVar_Init()

void CondVar_Init ( CondVar * cv )

Initializes a condition variable.

Parameters

cv	Pointer to the condition variable.

◆ CondVar_Signal()

static void CondVar_Signal ( CondVar * cv )

inlinestatic

Wakes up a single thread waiting on a condition variable.

Parameters

cv	Pointer to the condition variable.

◆ CondVar_Wait()

void CondVar_Wait	(	CondVar *	cv,
		LightLock *	lock
	)

Waits on a condition variable.

Parameters

cv	Pointer to the condition variable.
lock	Pointer to the lock to atomically unlock/relock during the wait.

◆ CondVar_WaitTimeout()

int CondVar_WaitTimeout	(	CondVar *	cv,
		LightLock *	lock,
		s64	timeout_ns
	)

Waits on a condition variable with a timeout.

Parameters

cv	Pointer to the condition variable.
lock	Pointer to the lock to atomically unlock/relock during the wait.
timeout_ns	Timeout in nanoseconds.

Returns: Zero on success, non-zero on failure.

◆ CondVar_WakeUp()

void CondVar_WakeUp	(	CondVar *	cv,
		s32	num_threads
	)

Wakes up threads waiting on a condition variable.

Parameters

cv	Pointer to the condition variable.
num_threads	Maximum number of threads to wake up (or ARBITRATION_SIGNAL_ALL to wake them all).

◆ LightEvent_Clear()

void LightEvent_Clear ( LightEvent * event )

Clears a light event.

Parameters

event Pointer to the event.

◆ LightEvent_Init()

void LightEvent_Init	(	LightEvent *	event,
		ResetType	reset_type
	)

Initializes a light event.

Parameters

event	Pointer to the event.
reset_type	Type of reset the event uses (RESET_ONESHOT/RESET_STICKY).

◆ LightEvent_Pulse()

void LightEvent_Pulse ( LightEvent * event )

Wakes up threads waiting on a sticky light event without signaling it.

If the event had been signaled before, it is cleared instead.

Parameters

event Pointer to the event.

◆ LightEvent_Signal()

void LightEvent_Signal ( LightEvent * event )

Signals a light event, waking up threads waiting on it.

Parameters

event Pointer to the event.

◆ LightEvent_TryWait()

int LightEvent_TryWait ( LightEvent * event )

Attempts to wait on a light event.

Parameters

event Pointer to the event.

Returns: Non-zero if the event was signaled, zero otherwise.

◆ LightEvent_Wait()

void LightEvent_Wait ( LightEvent * event )

Waits on a light event.

Parameters

event Pointer to the event.

◆ LightEvent_WaitTimeout()

int LightEvent_WaitTimeout	(	LightEvent *	event,
		s64	timeout_ns
	)

Waits on a light event until either the event is signaled or the timeout is reached.

Parameters

event	Pointer to the event.
timeout_ns	Timeout in nanoseconds.

Returns: Non-zero on timeout, zero otherwise.

◆ LightLock_Init()

void LightLock_Init ( LightLock * lock )

Initializes a light lock.

Parameters

lock	Pointer to the lock.

◆ LightLock_Lock()

void LightLock_Lock ( LightLock * lock )

Locks a light lock.

Parameters

lock	Pointer to the lock.

◆ LightLock_TryLock()

int LightLock_TryLock ( LightLock * lock )

Attempts to lock a light lock.

Parameters

lock	Pointer to the lock.

Returns: Zero on success, non-zero on failure.

◆ LightLock_Unlock()

void LightLock_Unlock ( LightLock * lock )

Unlocks a light lock.

Parameters

lock	Pointer to the lock.

◆ LightSemaphore_Acquire()

void LightSemaphore_Acquire	(	LightSemaphore *	semaphore,
		s32	count
	)

Acquires a light semaphore.

Parameters

semaphore	Pointer to the semaphore.
count	Acquire count

◆ LightSemaphore_Init()

void LightSemaphore_Init	(	LightSemaphore *	semaphore,
		s16	initial_count,
		s16	max_count
	)

Initializes a light semaphore.

Parameters

event	Pointer to the semaphore.
max_count	Initial count of the semaphore.
max_count	Maximum count of the semaphore.

◆ LightSemaphore_Release()

void LightSemaphore_Release	(	LightSemaphore *	semaphore,
		s32	count
	)

Releases a light semaphore.

Parameters

semaphore	Pointer to the semaphore.
count	Release count

◆ LightSemaphore_TryAcquire()

int LightSemaphore_TryAcquire	(	LightSemaphore *	semaphore,
		s32	count
	)

Attempts to acquire a light semaphore.

Parameters

semaphore	Pointer to the semaphore.
count	Acquire count

Returns: Zero on success, non-zero on failure

◆ RecursiveLock_Init()

void RecursiveLock_Init ( RecursiveLock * lock )

Initializes a recursive lock.

Parameters

lock	Pointer to the lock.

◆ RecursiveLock_Lock()

void RecursiveLock_Lock ( RecursiveLock * lock )

Locks a recursive lock.

Parameters

lock	Pointer to the lock.

◆ RecursiveLock_TryLock()

int RecursiveLock_TryLock ( RecursiveLock * lock )

Attempts to lock a recursive lock.

Parameters

lock	Pointer to the lock.

Returns: Zero on success, non-zero on failure.

◆ RecursiveLock_Unlock()

void RecursiveLock_Unlock ( RecursiveLock * lock )

Unlocks a recursive lock.

Parameters

lock	Pointer to the lock.

◆ syncArbitrateAddress()

Result syncArbitrateAddress	(	s32 *	addr,
		ArbitrationType	type,
		s32	value
	)

Function used to implement user-mode synchronization primitives.

Parameters

addr	Pointer to a signed 32-bit value whose address will be used to identify waiting threads.
type	Type of action to be performed by the arbiter
value	Number of threads to signal if using ARBITRATION_SIGNAL, or the value used for comparison.

This will perform an arbitration based on #type. The comparisons are done between #value and the value at the address #addr.

s32 val=0;
// Does *nothing* since val >= 0
syncArbitrateAddress(&val,ARBITRATION_WAIT_IF_LESS_THAN,0);

Note: Usage of this function entails an implicit Data Memory Barrier (dmb).

◆ syncArbitrateAddressWithTimeout()

Result syncArbitrateAddressWithTimeout	(	s32 *	addr,
		ArbitrationType	type,
		s32	value,
		s64	timeout_ns
	)

Function used to implement user-mode synchronization primitives (with timeout).

Parameters

addr	Pointer to a signed 32-bit value whose address will be used to identify waiting threads.
type	Type of action to be performed by the arbiter (must use ARBITRATION_WAIT_IF_LESS_THAN_TIMEOUT or ARBITRATION_DECREMENT_AND_WAIT_IF_LESS_THAN_TIMEOUT)
value	Number of threads to signal if using ARBITRATION_SIGNAL, or the value used for comparison.

This will perform an arbitration based on #type. The comparisons are done between #value and the value at the address #addr.

s32 val=0;
// Thread will wait for a signal or wake up after 10000000 nanoseconds because val < 1.
syncArbitrateAddressWithTimeout(&val,ARBITRATION_WAIT_IF_LESS_THAN_TIMEOUT,1,10000000LL);

Note: Usage of this function entails an implicit Data Memory Barrier (dmb).

Data Structures

Macros

Typedefs

Functions

Detailed Description

Function Documentation

◆ __ldrex()

◆ __ldrexb()

◆ __ldrexh()

◆ __strex()

◆ __strexb()

◆ __strexh()

◆ CondVar_Broadcast()

◆ CondVar_Init()

◆ CondVar_Signal()

◆ CondVar_Wait()

◆ CondVar_WaitTimeout()

◆ CondVar_WakeUp()

◆ LightEvent_Clear()

◆ LightEvent_Init()

◆ LightEvent_Pulse()

◆ LightEvent_Signal()

◆ LightEvent_TryWait()

◆ LightEvent_Wait()

◆ LightEvent_WaitTimeout()

◆ LightLock_Init()

◆ LightLock_Lock()

◆ LightLock_TryLock()

◆ LightLock_Unlock()

◆ LightSemaphore_Acquire()

◆ LightSemaphore_Init()

◆ LightSemaphore_Release()

◆ LightSemaphore_TryAcquire()

◆ RecursiveLock_Init()

◆ RecursiveLock_Lock()

◆ RecursiveLock_TryLock()

◆ RecursiveLock_Unlock()

◆ syncArbitrateAddress()

◆ syncArbitrateAddressWithTimeout()