private static void Error(IDTStack *stack, string message)
{
Panic.ESP = stack->ESP;
Panic.EBP = stack->EBP;
Panic.EIP = stack->EIP;
Panic.EAX = stack->EAX;
Panic.EBX = stack->EBX;
Panic.ECX = stack->ECX;
Panic.EDX = stack->EDX;
Panic.EDI = stack->EDI;
Panic.ESI = stack->ESI;
Panic.CS = stack->CS;
Panic.ErrorCode = stack->ErrorCode;
Panic.EFLAGS = stack->EFLAGS;
Panic.Interrupt = stack->Interrupt;
Panic.CR2 = Native.GetCR2();
Panic.FS = Native.GetFS();
Panic.Error(message);
}
/// <summary>
/// Allocate a physical page from the free list
/// </summary>
/// <returns>The page</returns>
Page *Allocate(uint num)
{
KernelMessage.Write("Request {0} pages...", num);
var cnt = 0;
if (lastAllocatedPage == null)
{
lastAllocatedPage = PageArray;
}
Page *p = lastAllocatedPage->Next;
while (true)
{
if (p == null)
{
p = PageArray;
}
if (p->Status == PageStatus.Free)
{
var head = p;
// Found free Page. Check now free range.
for (var i = 0; i < num; i++)
{
if (p == null)
{
break; // Reached end. SorRange is incomplete
}
if (p->Status != PageStatus.Free) // Used -> so we can abort the searach
{
break;
}
if (i == num - 1)
{ // all loops successful. So we found our range.
head->Tail = p;
head->PagesUsed = num;
p = head;
for (var n = 0; n < num; n++)
{
p->Status = PageStatus.Used;
p->Head = head;
p->Tail = head->Tail;
p = p->Next;
PagesUsed++;
}
lastAllocatedPage = p;
KernelMessage.WriteLine("Allocated from {0:X8} to {1:X8}", (uint)head->PhysicalAddress, (uint)head->Tail->PhysicalAddress);
return(head);
}
p = p->Next;
}
}
if (p->Tail != null)
{
p = p->Tail;
}
p = p->Next;
if (++cnt > PageCount)
{
break;
}
}
Panic.Error("PageFrameAllocator: No free Page found");
return(null);
}