/// <summary>
/// Creates a new page directory using only physical memory (used in Init)
/// </summary>
/// <param name="flags">The flags</param>
/// <returns>The page directory</returns>
public static PageDirectory *CreateNewDirectoryPhysically(PageFlags flags)
{
// Allocate a new block of physical memory to store our physical page in
PageDirectory *directory = (PageDirectory *)Heap.AlignedAlloc(0x1000, sizeof(PageDirectory));
directory->PhysicalDirectory = directory;
if (directory == null)
{
Panic.DoPanic("directory == null");
}
// Allocate the tables
for (int i = 0; i < 1024; i++)
{
PageTable *table = (PageTable *)PhysicalMemoryManager.Alloc();
if (table == null)
{
Panic.DoPanic("table == null");
}
Memory.Memclear(table, sizeof(PageTable));
// Note: At this point, virtual address == physical address due to identity mapping
directory->PhysicalTables[i] = (int)table | (int)flags;
directory->VirtualTables[i] = (int)table;
}
return(directory);
}
/// <summary>
/// Allocates a virtual address range
/// </summary>
/// <param name="size">The size</param>
/// <returns>The pointer to the block</returns>
public static void *AllocateVirtual(int size)
{
// Page align size
uint sizeAligned = AlignUp((uint)size);
// Allocate
int free = bitmap.FindFirstFreeRange((int)(sizeAligned / 0x1000), true);
int start = free * 0x1000;
int end = (int)(start + sizeAligned);
PageFlags flags = PageFlags.Present | PageFlags.Writable | PageFlags.UserMode;
for (int address = start; address < end; address += 0x1000)
{
int phys = (int)PhysicalMemoryManager.Alloc();
MapPage(KernelDirectory, phys, address, flags);
MapPage(CurrentDirectory, phys, address, flags);
}
// Clear the data before returning it for safety
Memory.Memclear((void *)start, size);
return((void *)start);
}
