/// <summary>
/// Swaps in the specified <see cref="MemoryPage"/> from disk. Currently implemented as XML for fun.
/// </summary>
/// <param name="winner">The <see cref="MemoryPage"/> that is being swapped in</param>
public void SwapIn(MemoryPage winner)
{
// Generate a filename based on address and page number
string filename = System.Environment.CurrentDirectory + "/page" + winner.pageNumber + "-" + winner.addrVirtual + ".xml";
if (File.Exists(filename) && winner.isValid == false)
{
//BinaryFormatter ser = new BinaryFormatter();
//Stream reader = new FileStream(filename, FileMode.Open);
XmlSerializer ser = new XmlSerializer(typeof(MemoryPageValue));
Stream fs = new FileStream(filename, FileMode.Open);
XmlReader reader = new XmlTextReader(fs);
// Load the MemoryPageValue in from Disk!
MemoryPageValue pageValue = (MemoryPageValue)ser.Deserialize(reader);
// Copy the bytes from Physical Memory so we don't pageFault in a Fault Hander
for (int i = 0; i < CPU.pageSize; i++)
{
CPU.physicalMemory[winner.addrPhysical + i] = pageValue.memory[i];
}
//Console.WriteLine("Swapping in page {0} at physical memory {1}",winner.pageNumber, winner.addrPhysical);
winner.accessCount = pageValue.accessCount;
winner.lastAccessed = pageValue.lastAccessed;
pageValue = null;
reader.Close();
fs.Close();
File.Delete(filename);
}
else //no swap file, do nothing
{
//Console.WriteLine(filename + " doesn't exist");
}
// We are now in memory and we were involved in Page Fault
winner.isValid = true;
winner.pageFaults++;
}
/// <summary>
/// Swaps the specified <see cref="MemoryPage"/> to disk. Currently implemented as XML for fun.
/// </summary>
/// <param name="victim">The <see cref="MemoryPage"/> to be swapped</param>
public void SwapOut(MemoryPage victim)
{
if (victim.isDirty)
{
// Generate a filename based on address and page number
string filename = System.Environment.CurrentDirectory + "/page" + victim.pageNumber + "-" + victim.addrVirtual + ".xml";
// IFormatter ser = new BinaryFormatter();
// Stream writer = new FileStream(filename, FileMode.Create);
XmlSerializer ser = new XmlSerializer(typeof(MemoryPageValue));
Stream fs = new FileStream(filename, FileMode.Create);
XmlWriter writer = new XmlTextWriter(fs, new UTF8Encoding());
MemoryPageValue pageValue = new MemoryPageValue();
// Copy the bytes from Physical Memory so we don't pageFault in a Fault Hander
byte[] bytes = new byte[CPU.pageSize];
for (int i = 0; i < CPU.pageSize; i++)
{
bytes[i] = CPU.physicalMemory[victim.addrPhysical + i];
}
// Copy details from the MemoryPage to the MemoryPageValue
pageValue.memory = bytes;
pageValue.accessCount = victim.accessCount;
pageValue.lastAccessed = victim.lastAccessed;
//Console.WriteLine("Swapping out page {0} at physical memory {1}",victim.pageNumber, victim.addrPhysical);
// Write the MemoryPageValue to disk!
ser.Serialize(writer, pageValue);
//writer.Flush();
//writer.Close();
fs.Close();
}
victim.isValid = false;
}
