// Low-level routines based on the operating system interface
private static unsafe UIntPtr AllocateMemoryHelper(UIntPtr startAddr,
UIntPtr size)
{
void *result = VirtualAlloc((void *)startAddr,
size, MEM_RESERVE, PAGE_READWRITE);
VTable.Assert
(PageTable.Page((UIntPtr)result + size - 1)
< PageTable.pageTableCount,
"OutOfMemory: MemoryManager: memory doesn't fit in page table");
if (result != null)
{
Trace.Log(Trace.Area.Page,
"VirtualAlloc {0} at {1}",
__arglist(size, result));
VTable.Assert((startAddr == UIntPtr.Zero) ||
(result == (void *)startAddr));
void *area = VirtualAlloc(result, size,
MEM_COMMIT, PAGE_READWRITE);
if (PageTable.halPageDescriptor != null)
{
PageTable.CreateNewPageTablesIfNecessary(PageTable.Page((UIntPtr)result), PageTable.PageCount(size));
PageTable.SetProcess(PageTable.Page((UIntPtr)area),
PageTable.PageCount(size));
}
VTable.Assert(result == area);
#if HIMEM
// This assertion intends only to catch bugs in Bartok. But if
// the system (windows) frees memory before, the memory
// may be in low memory, and if we happen to get that
// memory, this assertion itself may not hold
VTable.Assert((UIntPtr)result >= PageTable.HIMEMStart,
("High memory is expected to be allocated in HIMEM mode"));
#endif
}
return(new UIntPtr(result));
}