public long SignalAndIncrementIfEqual(AMemory Memory, long Address, int Value, int Count)
{
System.CriticalSectionLock.Lock();
Memory.SetExclusive(0, Address);
if (!UserToKernelInt32(Memory, Address, out int CurrentValue))
{
System.CriticalSectionLock.Unlock();
return(MakeError(ErrorModule.Kernel, KernelErr.NoAccessPerm));
}
while (CurrentValue == Value)
{
if (Memory.TestExclusive(0, Address))
{
Memory.WriteInt32(Address, CurrentValue + 1);
Memory.ClearExclusiveForStore(0);
break;
}
Memory.SetExclusive(0, Address);
CurrentValue = Memory.ReadInt32(Address);
}
Memory.ClearExclusive(0);
if (CurrentValue != Value)
{
System.CriticalSectionLock.Unlock();
return(MakeError(ErrorModule.Kernel, KernelErr.InvalidState));
}
WakeArbiterThreads(Address, Count);
System.CriticalSectionLock.Unlock();
return(0);
}
public long SignalAndModifyIfEqual(AMemory Memory, long Address, int Value, int Count)
{
System.CriticalSectionLock.Lock();
int Offset;
//The value is decremented if the number of threads waiting is less
//or equal to the Count of threads to be signaled, or Count is zero
//or negative. It is incremented if there are no threads waiting.
int WaitingCount = 0;
foreach (KThread Thread in ArbiterThreads.Where(x => x.MutexAddress == Address))
{
if (++WaitingCount > Count)
{
break;
}
}
if (WaitingCount > 0)
{
Offset = WaitingCount <= Count || Count <= 0 ? -1 : 0;
}
else
{
Offset = 1;
}
Memory.SetExclusive(0, Address);
if (!UserToKernelInt32(Memory, Address, out int CurrentValue))
{
System.CriticalSectionLock.Unlock();
return(MakeError(ErrorModule.Kernel, KernelErr.NoAccessPerm));
}
while (CurrentValue == Value)
{
if (Memory.TestExclusive(0, Address))
{
Memory.WriteInt32(Address, CurrentValue + Offset);
Memory.ClearExclusiveForStore(0);
break;
}
Memory.SetExclusive(0, Address);
CurrentValue = Memory.ReadInt32(Address);
}
Memory.ClearExclusive(0);
if (CurrentValue != Value)
{
System.CriticalSectionLock.Unlock();
return(MakeError(ErrorModule.Kernel, KernelErr.InvalidState));
}
WakeArbiterThreads(Address, Count);
System.CriticalSectionLock.Unlock();
return(0);
}
public long WaitForAddressIfLessThan(
AMemory Memory,
long Address,
int Value,
bool ShouldDecrement,
long Timeout)
{
KThread CurrentThread = System.Scheduler.GetCurrentThread();
System.CriticalSectionLock.Lock();
if (CurrentThread.ShallBeTerminated ||
CurrentThread.SchedFlags == ThreadSchedState.TerminationPending)
{
System.CriticalSectionLock.Unlock();
return(MakeError(ErrorModule.Kernel, KernelErr.ThreadTerminating));
}
CurrentThread.SignaledObj = null;
CurrentThread.ObjSyncResult = (int)MakeError(ErrorModule.Kernel, KernelErr.Timeout);
//If ShouldDecrement is true, do atomic decrement of the value at Address.
Memory.SetExclusive(0, Address);
if (!UserToKernelInt32(Memory, Address, out int CurrentValue))
{
System.CriticalSectionLock.Unlock();
return(MakeError(ErrorModule.Kernel, KernelErr.NoAccessPerm));
}
if (ShouldDecrement)
{
while (CurrentValue < Value)
{
if (Memory.TestExclusive(0, Address))
{
Memory.WriteInt32(Address, CurrentValue - 1);
Memory.ClearExclusiveForStore(0);
break;
}
Memory.SetExclusive(0, Address);
CurrentValue = Memory.ReadInt32(Address);
}
}
Memory.ClearExclusive(0);
if (CurrentValue < Value)
{
if (Timeout == 0)
{
System.CriticalSectionLock.Unlock();
return(MakeError(ErrorModule.Kernel, KernelErr.Timeout));
}
CurrentThread.MutexAddress = Address;
CurrentThread.WaitingInArbitration = true;
InsertSortedByPriority(ArbiterThreads, CurrentThread);
CurrentThread.Reschedule(ThreadSchedState.Paused);
if (Timeout > 0)
{
System.TimeManager.ScheduleFutureInvocation(CurrentThread, Timeout);
}
System.CriticalSectionLock.Unlock();
if (Timeout > 0)
{
System.TimeManager.UnscheduleFutureInvocation(CurrentThread);
}
System.CriticalSectionLock.Lock();
if (CurrentThread.WaitingInArbitration)
{
ArbiterThreads.Remove(CurrentThread);
CurrentThread.WaitingInArbitration = false;
}
System.CriticalSectionLock.Unlock();
return(CurrentThread.ObjSyncResult);
}
System.CriticalSectionLock.Unlock();
return(MakeError(ErrorModule.Kernel, KernelErr.InvalidState));
}
private KThread TryAcquireMutex(Process Process, AMemory Memory, KThread Requester)
{
long Address = Requester.MutexAddress;
Memory.SetExclusive(0, Address);
if (!UserToKernelInt32(Memory, Address, out int MutexValue))
{
//Invalid address.
Memory.ClearExclusive(0);
Requester.SignaledObj = null;
Requester.ObjSyncResult = (int)MakeError(ErrorModule.Kernel, KernelErr.NoAccessPerm);
return(null);
}
while (true)
{
if (Memory.TestExclusive(0, Address))
{
if (MutexValue != 0)
{
//Update value to indicate there is a mutex waiter now.
Memory.WriteInt32(Address, MutexValue | HasListenersMask);
}
else
{
//No thread owning the mutex, assign to requesting thread.
Memory.WriteInt32(Address, Requester.ThreadHandleForUserMutex);
}
Memory.ClearExclusiveForStore(0);
break;
}
Memory.SetExclusive(0, Address);
MutexValue = Memory.ReadInt32(Address);
}
if (MutexValue == 0)
{
//We now own the mutex.
Requester.SignaledObj = null;
Requester.ObjSyncResult = 0;
Requester.ReleaseAndResume();
return(null);
}
MutexValue &= ~HasListenersMask;
KThread MutexOwner = Process.HandleTable.GetObject <KThread>(MutexValue);
if (MutexOwner != null)
{
//Mutex already belongs to another thread, wait for it.
MutexOwner.AddMutexWaiter(Requester);
}
else
{
//Invalid mutex owner.
Requester.SignaledObj = null;
Requester.ObjSyncResult = (int)MakeError(ErrorModule.Kernel, KernelErr.InvalidHandle);
Requester.ReleaseAndResume();
}
return(MutexOwner);
}