DllStdCall

function DllStdCall(DllName: string; FuncName: string; Params: array of const): Integer;
var
  DllHandle: Cardinal;
  FuncAddr : Pointer;
  Param    : TVarRec;
  I        : Integer;
begin
  DllHandle := LoadLibrary(PChar(DllName));
  if DllHandle = 0 then
    raise Exception.Create('Can''t load dll ' + DllName);

  FuncAddr := GetProcAddress(DllHandle, PChar(FuncName));

  if FuncAddr = nil then
    raise Exception.Create(FuncName + ' not found');

  for I := High(Params) downto 0 do
  begin
    Param := Params[I];
    case Params[I].VType of
      vtInteger:
      asm
        push Param.VInteger;
      end;
      vtBoolean:
      asm
        push Integer(Param.VBoolean);
      end;
      vtChar:
      asm
        push Integer(Param.VChar);
      end;
      vtExtended:
      asm
        push Param.VExtended;
      end;
      vtString:
      asm
        push Param.VString;
      end;
      vtPChar:
      asm
        push Param.VPChar;
      end;
      vtObject:
      asm
        push Param.VObject;
      end;
      vtClass:
      asm
        push Param.VClass;
      end;
      vtAnsiString:
      asm
        push Param.VAnsiString;
      end;
      vtUnicodeString:
      asm
        push Param.VUnicodeString;
      end;
      vtCurrency:
      asm
        push Param.VCurrency;
      end;
      vtInt64:
      asm
        push Param.VInt64;
      end;
      vtPointer:
      asm
        push Param.VPointer;
      end;
      vtWideChar:
      asm
        push Param.VWideChar;
      end;
      vtPWideChar:
      asm
        push Param.VPWideChar;
      end;
      else
        raise Exception.Create('Unsuported Type');
    end;
  end;
  asm
    call FuncAddr;
    mov Result, EAX;
  end;
end;