public void WriteBack(ushort pageIndex, ushort frameIndex)
{
TlbEntry newEntry = new TlbEntry(pageIndex, frameIndex);
//look for an empty entry
for (int i = 0; i < EntriesPerTLB; i++)
{
if (_entries[i].PageIndex == null)
{
_entries[i] = newEntry;
return;
}
}
//swap a resident entry with a biggest counter
int maxValue = 0, maxIndex = 0;
for (int i = 0; i < EntriesPerTLB; i++)
{
if (_entries[i].Counter > maxValue)
{
maxValue = _entries[i].Counter;
maxIndex = i;
}
}
_entries[maxIndex] = newEntry;
}
public TLB()
{
for (int i = 0; i < 16; i++)
{
_entries[i] = new TlbEntry();
}
}
internal static (int index, TlbEntry entry) CreateTlbEntry(uint virtualAddress,
uint physicalAddress, bool rw = true, bool supervisor = false)
{
var entry = physicalAddress & 0xFFFFFC00;
entry |= rw ? PageTableFlags.Rw : 0;
entry |= supervisor ? PageTableFlags.Supervisor : 0;
var tag = TlbEntry.TagFromAddress(virtualAddress);
var tlbEntry = new TlbEntry
{
entry = entry,
tag = tag,
};
var index = TlbEntry.IndexFromTag(tag);
return(index, tlbEntry);
}