NIOS II SPI communication

I tried to write a simple code section in C language to make SPI communication, with NIOS as slave. Can you check if my code is good please?

static void spi_rx_isr(void* isr_context);

static void spi_rx_isr(void* isr_context){

IOWR_ALTERA_AVALON_SPI_STATUS(SPI_SLAVE_BASE, 0x0);

}

int ret;

int status;

alt_u16 rddata;

//this registers slave IRQ with NIOS

ret = alt_iic_isr_register(SPI_SLAVE_IRQ_INTERRUPT_CONTROLLER_ID,SPI_SLAVE_IRQ,spi_rx_isr,(void *)spi_command_string_tx,0x0);

//check if slave status is good

do{

status = IORD_ALTERA_AVALON_SPI_STATUS(SPI_SLAVE_BASE);

}

while ((status & ALTERA_AVALON_SPI_STATUS_RRDY_MSK) == 0);

//copy received byte into rddata variable

rddata = IORD_ALTERA_AVALON_SPI_RXDATA(SPI_SLAVE_BASE);

//set slave IRQ to enable a new byte receiving

IOWR_ALTERA_AVALON_SPI_CONTROL(SPI_SLAVE_BASE, ALTERA_AVALON_SPI_CONTROL_SSO_MSK | ALTERA_AVALON_SPI_CONTROL_IRRDY_MSK);