/// <summary>
/// Gets the address of an unused (free) region of the specified size.
/// </summary>
/// <param name="size">Size of the region in bytes</param>
/// <param name="freeAddressStartPosition">Position at which memory can be allocated</param>
/// <param name="alignment">Required alignment of the region address in bytes</param>
/// <param name="start">Start address of the search on the address space</param>
/// <returns>GPU virtual address of the allocation, or an all ones mask in case of failure</returns>
public ulong GetFreeAddress(ulong size, out ulong freeAddressStartPosition, ulong alignment = 1, ulong start = DefaultStart)
{
// Note: Address 0 is not considered valid by the driver,
// when 0 is returned it's considered a mapping error.
lock (_tree)
{
Logger.Debug?.Print(LogClass.ServiceNv, $"Searching for a free address @ 0x{start:X} of size 0x{size:X}.");
ulong address = start;
if (alignment == 0)
{
alignment = 1;
}
alignment = (alignment + PageMask) & ~PageMask;
if (address < AddressSpaceSize)
{
bool reachedEndOfAddresses = false;
ulong targetAddress;
if (start == DefaultStart)
{
Logger.Debug?.Print(LogClass.ServiceNv, $"Target address set to start of the last available range: 0x{_list.Last.Value:X}.");
targetAddress = _list.Last.Value;
}
else
{
targetAddress = _tree.Floor(address);
Logger.Debug?.Print(LogClass.ServiceNv, $"Target address set to floor of 0x{address:X}; resulted in 0x{targetAddress:X}.");
if (targetAddress == InvalidAddress)
{
targetAddress = _tree.Ceiling(address);
Logger.Debug?.Print(LogClass.ServiceNv, $"Target address was invalid, set to ceiling of 0x{address:X}; resulted in 0x{targetAddress:X}");
}
}
while (address < AddressSpaceSize)
{
if (targetAddress != InvalidAddress)
{
if (address >= targetAddress)
{
if (address + size <= _tree.Get(targetAddress))
{
Logger.Debug?.Print(LogClass.ServiceNv, $"Found a suitable free address range from 0x{targetAddress:X} to 0x{_tree.Get(targetAddress):X} for 0x{address:X}.");
freeAddressStartPosition = targetAddress;
return(address);
}
else
{
Logger.Debug?.Print(LogClass.ServiceNv, "Address requirements exceeded the available space in the target range.");
LinkedListNode <ulong> nextPtr = _dictionary[targetAddress];
if (nextPtr.Next != null)
{
targetAddress = nextPtr.Next.Value;
Logger.Debug?.Print(LogClass.ServiceNv, $"Moved search to successor range starting at 0x{targetAddress:X}.");
}
else
{
if (reachedEndOfAddresses)
{
Logger.Debug?.Print(LogClass.ServiceNv, "Exiting loop, a full pass has already been completed w/ no suitable free address range.");
break;
}
else
{
reachedEndOfAddresses = true;
address = start;
targetAddress = _tree.Floor(address);
Logger.Debug?.Print(LogClass.ServiceNv, $"Reached the end of the available free ranges, restarting loop @ 0x{targetAddress:X} for 0x{address:X}.");
}
}
}
}
else
{
address += PageSize * (targetAddress / PageSize - (address / PageSize));
ulong remainder = address % alignment;
if (remainder != 0)
{
address = (address - remainder) + alignment;
}
Logger.Debug?.Print(LogClass.ServiceNv, $"Reset and aligned address to {address:X}.");
if (address + size > AddressSpaceSize && !reachedEndOfAddresses)
{
reachedEndOfAddresses = true;
address = start;
targetAddress = _tree.Floor(address);
Logger.Debug?.Print(LogClass.ServiceNv, $"Address requirements exceeded the capacity of available address space, restarting loop @ 0x{targetAddress:X} for 0x{address:X}.");
}
}
}
else
{
break;
}
}
}
Logger.Debug?.Print(LogClass.ServiceNv, $"No suitable address range found; returning: 0x{InvalidAddress:X}.");
freeAddressStartPosition = InvalidAddress;
}
return(PteUnmapped);
}
