One solution is to convert the DWORD to a comp.

Example:
{$IFOPT Q+}
  {$DEFINE OVERFLOWSON}
  {$Q-}
{$ENDIF}
function DWordToComp(dw : longint) : comp;
var
  c : comp;
begin
  if u >= 0 then
    c := dw else begin
    c := $7FFFFFFF;
    if dw = -  then
      c := c + c +  
    else
      c := c + abs($7FFFFFFF - dw);
  end;
  result := c;
end;
{$IFDEF OVERFLOWSON}
  {$UNDEF OVERFLOWSON}
  {$Q+}
{$ENDIF}