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void move_stack(void *new_stack_start, u32int size)
{
  u32int i;
  // Allocate some space for the new stack.
  for( i = (u32int)new_stack_start;
       i >= ((u32int)new_stack_start-size);
       i -= 0x1000)
  {
    // General-purpose stack is in user-mode.
    alloc_frame( get_page(i, 1, current_directory), 0 /* User mode */, 1 /* Is writable */ );
  }
  
  // Flush the TLB by reading and writing the page directory address again.
  u32int pd_addr;
  asm volatile("mov %%cr3, %0" : "=r" (pd_addr));
  asm volatile("mov %0, %%cr3" : : "r" (pd_addr));

  // Old ESP and EBP, read from registers.
  u32int old_stack_pointer; asm volatile("mov %%esp, %0" : "=r" (old_stack_pointer));
  u32int old_base_pointer;  asm volatile("mov %%ebp, %0" : "=r" (old_base_pointer));

  // Offset to add to old stack addresses to get a new stack address.
  u32int offset            = (u32int)new_stack_start - initial_esp;          // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

  // New ESP and EBP.
  u32int new_stack_pointer = old_stack_pointer + offset;
  u32int new_base_pointer  = old_base_pointer  + offset;

  // Copy the stack.
  memcpy((void*)new_stack_pointer, (void*)old_stack_pointer, initial_esp-old_stack_pointer);

  // Backtrace through the original stack, copying new values into
  // the new stack.  
  for(i = (u32int)new_stack_start; i > (u32int)new_stack_start-size; i -= 4)
  {
    u32int tmp = * (u32int*)i;
    // If the value of tmp is inside the range of the old stack, assume it is a base pointer
    // and remap it. This will unfortunately remap ANY value in this range, whether they are
    // base pointers or not.
    if (( old_stack_pointer < tmp) && (tmp < initial_esp))
    {
      tmp = tmp + offset;
      u32int *tmp2 = (u32int*)i;
      *tmp2 = tmp;
    }
  }

  // Change stacks.
  asm volatile("mov %0, %%esp" : : "r" (new_stack_pointer));
  asm volatile("mov %0, %%ebp" : : "r" (new_base_pointer));
}