internal static unsafe void SetFirst(UIntPtr newAddr)
{
VTable.Assert(PageTable.IsGcPage(PageTable.Page(newAddr)),
"SetFirst on a non-GC page");
UIntPtr page = PageTable.Page(newAddr);
UIntPtr offset = newAddr - PageTable.PageAddr(page);
PageTable.SetExtra(page, unchecked ((uint)(offset + OFFSET_SKEW)));
}
// Bartok uses the extra field in the PageTable to easily
// map from a stack address to the thread that owns that stack.
// This is used to implement GetCurrentThread.
// Singularity uses a different mechanism that does not involve
// the extra data at all.
private static unsafe void SetStackPages(UIntPtr startAddr,
UIntPtr endAddr,
Thread thread)
{
UIntPtr startPage = PageTable.Page(startAddr);
UIntPtr endPage = PageTable.Page(endAddr);
UIntPtr pageCount = endPage - startPage;
PageTable.VerifyType(startPage, pageCount, PageType.Unallocated);
PageTable.VerifyExtra(startPage, pageCount, 0);
PageTable.SetType(startPage, pageCount, PageType.Stack);
PageTable.SetExtra(startPage, pageCount,
(uint)thread.threadIndex);
}
// Tell the GC that a certain data area is no longer allowed to
// contain off-limits, non-moveable data.
private static unsafe void SetUnallocatedPages(UIntPtr startAddr,
UIntPtr size)
{
UIntPtr startPage = PageTable.Page(startAddr);
UIntPtr endAddr = startAddr + size;
UIntPtr endPage = PageTable.Page(endAddr);
UIntPtr pageCount = endPage - startPage;
if (pageCount == 1)
{
PageTable.SetExtra(startPage, 0);
PageTable.SetType(startPage, PageType.Unallocated);
PageTable.SetProcess(startPage, 0);
}
else
{
PageTable.SetExtra(startPage, pageCount, 0);
PageTable.SetType(startPage, pageCount, PageType.Unallocated);
PageTable.SetProcess(startPage, pageCount, 0);
}
}
internal static unsafe void ClearFirst(UIntPtr startPage,
UIntPtr endPage)
{
PageTable.SetExtra(startPage, endPage - startPage, OFFSET_NO_DATA);
}
internal static unsafe void ClearFirst(UIntPtr page)
{
PageTable.SetExtra(page, OFFSET_NO_DATA);
}