Ryujinx/src/Ryujinx.Memory/PageTable.cs
2023-04-27 23:51:14 +02:00

141 lines
3.7 KiB
C#

namespace Ryujinx.Memory
{
public class PageTable<T> where T : unmanaged
{
public const int PageBits = 12;
public const int PageSize = 1 << PageBits;
public const int PageMask = PageSize - 1;
private const int PtLevelBits = 9; // 9 * 4 + 12 = 48 (max address space size)
private const int PtLevelSize = 1 << PtLevelBits;
private const int PtLevelMask = PtLevelSize - 1;
private readonly T[][][][] _pageTable;
public PageTable()
{
_pageTable = new T[PtLevelSize][][][];
}
public T Read(ulong va)
{
int l3 = (int)(va >> PageBits) & PtLevelMask;
int l2 = (int)(va >> (PageBits + PtLevelBits)) & PtLevelMask;
int l1 = (int)(va >> (PageBits + PtLevelBits * 2)) & PtLevelMask;
int l0 = (int)(va >> (PageBits + PtLevelBits * 3)) & PtLevelMask;
if (_pageTable[l0] == null)
{
return default;
}
if (_pageTable[l0][l1] == null)
{
return default;
}
if (_pageTable[l0][l1][l2] == null)
{
return default;
}
return _pageTable[l0][l1][l2][l3];
}
public void Map(ulong va, T value)
{
int l3 = (int)(va >> PageBits) & PtLevelMask;
int l2 = (int)(va >> (PageBits + PtLevelBits)) & PtLevelMask;
int l1 = (int)(va >> (PageBits + PtLevelBits * 2)) & PtLevelMask;
int l0 = (int)(va >> (PageBits + PtLevelBits * 3)) & PtLevelMask;
if (_pageTable[l0] == null)
{
_pageTable[l0] = new T[PtLevelSize][][];
}
if (_pageTable[l0][l1] == null)
{
_pageTable[l0][l1] = new T[PtLevelSize][];
}
if (_pageTable[l0][l1][l2] == null)
{
_pageTable[l0][l1][l2] = new T[PtLevelSize];
}
_pageTable[l0][l1][l2][l3] = value;
}
public void Unmap(ulong va)
{
int l3 = (int)(va >> PageBits) & PtLevelMask;
int l2 = (int)(va >> (PageBits + PtLevelBits)) & PtLevelMask;
int l1 = (int)(va >> (PageBits + PtLevelBits * 2)) & PtLevelMask;
int l0 = (int)(va >> (PageBits + PtLevelBits * 3)) & PtLevelMask;
if (_pageTable[l0] == null)
{
return;
}
if (_pageTable[l0][l1] == null)
{
return;
}
if (_pageTable[l0][l1][l2] == null)
{
return;
}
_pageTable[l0][l1][l2][l3] = default;
bool empty = true;
for (int i = 0; i < _pageTable[l0][l1][l2].Length; i++)
{
empty &= _pageTable[l0][l1][l2][i].Equals(default);
}
if (empty)
{
_pageTable[l0][l1][l2] = null;
RemoveIfAllNull(l0, l1);
}
}
private void RemoveIfAllNull(int l0, int l1)
{
bool empty = true;
for (int i = 0; i < _pageTable[l0][l1].Length; i++)
{
empty &= (_pageTable[l0][l1][i] == null);
}
if (empty)
{
_pageTable[l0][l1] = null;
RemoveIfAllNull(l0);
}
}
private void RemoveIfAllNull(int l0)
{
bool empty = true;
for (int i = 0; i < _pageTable[l0].Length; i++)
{
empty &= (_pageTable[l0][i] == null);
}
if (empty)
{
_pageTable[l0] = null;
}
}
}
}