DOS Unit
                              Flag Constants

      These constants are used to test the individual flag bits in the
      Flags register after a call to Intr or MsDos.

                             FCarry       = $0001;
                             FParity      = $0004;
                             FAuxiliary   = $0010;
                             FZero        = $0040;
                             FSign        = $0080;
                             FOverflow    = $0800;