public void performWrite(int address, int data, long cycles) {
    System.out.println("TFE_CS8900: write " + Integer.toString(address, 16)
		       + " = " + data);
    address -= offset;
    switch (address) {
    case PPDATA:
      break;
    case PPDATA + 1:
      break;
    case PACKET_PP:
      break;
    case PACKET_PP + 1:
      break;
    case TXCMD:
      break;
    case TXLEN:
      break;
    case RXTXREG:
      break;
    case RXTXREG + 1:
      break;
    }
  }