说明：  MPC8541的GPIO访问
(MPC8541 visit the GPIO# define GPIO_REG (type, port) (M8260_IOP_P port#### type (GPIO_IMMR_ BASE))# define gpioRegGet (type, port, reg) do (if (port == PORT_A) reg = (NW_VUINT32*) GPIO_REG (type, A) else if (port == PORT_B) reg = (NW_VUINT32*) G PIO_REG (type, B) else if (port == PORT_C) reg = (NW_VUINT32*) G PIO_REG (type, C) else if (port == PORT_D) reg = (NW_VUINT32*) G PIO_REG (type D) else reg = NULL;) while (0))