public TLBEntry(Boolean addressMode, Byte asid, Int64 virtualAddress, PageSize size)
: this(addressMode)
{
/* This is a hack to create entries without using the TLB regs */
m_Vpn2 = new VirtualPageNumber2(asid, (UInt64)virtualAddress & size.AddressBaseMask);
m_PageSize = size;
}
public byte GetIndex(VirtualPageNumber2 vpn2)
{
return((Byte)
(from index in Enumerable.Range(0, m_Entries.Length)
let entry = m_Entries[index]
where entry != null && entry.Equals(vpn2)
select index).First());
}
public TLBEntry(Boolean addressMode = false)
{
m_AddressingMode = addressMode;
m_PageSize = new PageSize(NamedPageSize.Size4KB);
m_Vpn2 = new VirtualPageNumber2();
m_EntryEven = new PageFrameNumber();
m_EntryOdd = new PageFrameNumber();
}
public long TranslateVirtualAddress(long virtualAddress)
{
VirtualPageNumber2 vpn2 = new VirtualPageNumber2(m_Cp0Regs.EntryHi);
PageSize pageSize = new PageSize(m_Cp0Regs.PageMask);
TLBEntry entry = null;
/* Note:
* We are assuming the software set ASID and VPN in the EntryHi when comparing
* the virtual address with the TLB cache. Without a real test of this,
* we don't know truly know if we rely on EntryHi every time there is a translation
* to be performed. I do not understand how the TLB is really even used on the N64
* system, virtual memory is useless without having some kind of pagefile.
*/
if (m_DuplicateEntryError)
{
// TODO: Set the TS bit in the status register
m_DisableTLB = true;
return(-1);
}
/* Access the global entries first */
if (!m_GlobalVPN2Dictionary.TryGetValue(vpn2, out entry))
{
/* If nothing is in global table, then access the entries grouped by an ASID */
if (!m_VPN2Dictionary.TryGetValue(vpn2, out entry))
{
throw new TLBException(TLBExceptionType.Refill);
}
}
Boolean isOddPage = ((virtualAddress & pageSize.Size) > 0) ? false : true;
PageFrameNumber pfn = isOddPage ? entry.PfnOdd : entry.PfnEven;
if (pfn.IsValid)
{
return(pfn.MapPhysical(pageSize, (UInt64)virtualAddress));
}
else
{
throw new TLBException(TLBExceptionType.Refill);
}
}
/// <summary>
/// If successful, the probe returns the entry index matching the VPN2 / ASID values in EntryHi.
/// </summary>
/// <remarks>
/// Ref: MIPS R4300I Manual Page 637
/// Ref: MIPS R4300I Manual Page 115
/// </remarks>
public virtual void Probe()
{
if (m_DisableTLB)
{
return;
}
UpdateRandom();
VirtualPageNumber2 vpn2 = new VirtualPageNumber2(m_Cp0Regs.EntryHi);
if (ContainsEntry(vpn2))
{
/* Get the entry index */
m_Cp0Regs.Index = GetIndex(vpn2);
}
else
{
/* Set P bit to 1 indicating the probe has failed */
m_Cp0Regs.Index = 0x80000000;
}
}
private bool ContainsEntry(VirtualPageNumber2 vpn2)
{
return(m_VPN2Dictionary.ContainsKey(vpn2));
}
public bool Equals(VirtualPageNumber2 other)
{
return
(IsGlobal ? true : VPN2.Asid == other.Asid &&
VPN2.Vpn2 == other.Vpn2);
}