public void putBus_toUse(int pID, CacheAccessResult result, MESI_States pS, bool used = false)
{
if (this.waitingProcessors.Count == 0) //First entry into the queue else the bus would already be in use.
{
this.useCycles = 0;
this.inUse = true;
}
blockingInfo temp;
temp.processorId = pID;
temp.processorState = pS;
temp.result = result;
this.waitingProcessors.Enqueue(temp);
}
public void putBus_toUse(int pID, CacheAccessResult result, MESI_States pS, bool used = false)
{
if (this.waitingProcessors.Count == 0) //First entry into the queue else the bus would already be in use.
{
this.useCycles = 0;
this.inUse = true;
}
blockingInfo temp;
temp.processorId = pID;
temp.processorState = pS;
temp.result = result;
this.waitingProcessors.Enqueue(temp);
}
private void snoopBus(int sendingProcessorId)
{
int slot = convertBinarytoDecimal(slotAddress);
bool sharedSignal = false;
int processorSupplyingData = -1;
BusSignals servingSignal = bus.pendingSignal.Peek();
#region otherProcessorsSnooping
foreach (var processor in processors) //each processor snoops the bus
{
if (processor.L1.blocks[slot].tag != tagAddress || processor.processorId == sendingProcessorId) //The processor does not have that data and do not process the signal on the sending processor.
{
continue;
}
else
{
MESI_States ownState = processor.L1.blocks[slot].currentState;
switch (servingSignal)
{
case BusSignals.BusRd:
switch (ownState)
{
case MESI_States.Modified:
//flush data to memory
flushData();
processor.L1.blocks[slot].currentState = MESI_States.Shared;
sharedSignal = true;
processorSupplyingData = processor.processorId;
break;
case MESI_States.Exclusive:
processor.L1.blocks[slot].currentState = MESI_States.Shared;
sharedSignal = true;
processorSupplyingData = processor.processorId;
break;
case MESI_States.Shared:
//do nothing. let it be at shared
sharedSignal = true;
processorSupplyingData = processor.processorId;
break;
case MESI_States.Invalid:
//do nothing.
break;
default:
break;
}
break;
case BusSignals.BusRdX:
switch (ownState)
{
case MESI_States.Modified:
flushData();
processor.L1.blocks[slot].currentState = MESI_States.Invalid;
processorSupplyingData = processor.processorId;
break;
case MESI_States.Exclusive:
processor.L1.blocks[slot].currentState = MESI_States.Invalid;
processorSupplyingData = processor.processorId;
break;
case MESI_States.Shared:
processor.L1.blocks[slot].currentState = MESI_States.Invalid;
processorSupplyingData = processor.processorId;
break;
case MESI_States.Invalid:
//do nothing.
break;
default:
break;
}
break;
case BusSignals.BusInvalidate:
switch (ownState)
{
case MESI_States.Modified:
//not possible. Only the sending processor can have modified data.
break;
case MESI_States.Exclusive:
processor.L1.blocks[slot].currentState = MESI_States.Invalid;
break;
case MESI_States.Shared:
processor.L1.blocks[slot].currentState = MESI_States.Invalid;
break;
case MESI_States.Invalid:
//do nothing.
break;
default:
break;
}
break;
case BusSignals.NoSignal:
//do nothing.
break;
default:
break;
}
}
}
#endregion
#region respondingToResponse
//update the sending processor's state.
switch (servingSignal)
{
case BusSignals.BusRd:
//the processor did not have the data. It will go into Exclusive or Shared state depending on if the shared signal was raised.
if (sharedSignal == true)
{
processors[sendingProcessorId].L1.blocks[slot].currentState = MESI_States.Shared;
//store data
processors[sendingProcessorId].L1.blocks[slot].tag = processors[processorSupplyingData].L1.blocks[slot].tag;
}
else
{
processors[sendingProcessorId].L1.blocks[slot].currentState = MESI_States.Exclusive;
//store data
processors[sendingProcessorId].L1.blocks[slot].tag = tagAddress;
}
break;
case BusSignals.BusRdX:
//It will have modified (dirty) data coz it is asking for data with intent to modify
processors[sendingProcessorId].L1.blocks[slot].currentState = MESI_States.Modified;
if (processorSupplyingData != -1) //if some processor had this data
//store data
{
processors[sendingProcessorId].L1.blocks[slot].tag = processors[processorSupplyingData].L1.blocks[slot].tag;
}
else
{
//store data
processors[sendingProcessorId].L1.blocks[slot].tag = tagAddress;
}
break;
case BusSignals.BusInvalidate:
//It is about to modify its own copy.
processors[sendingProcessorId].L1.blocks[slot].currentState = MESI_States.Modified;
break;
case BusSignals.NoSignal:
break;
default:
break;
}
#endregion
bus.pendingSignal.Dequeue(); //Signal has been served.
}