SPI between Master arduino and Slave arduino

Question

How can I send the string from Slave SPI to Master SPI?

I want to write code in Bare Metal.

The problem which I am facing is I can't make out what will be my blocking function in Master SPI code when receiving data from slave SPI.

As my SPIF bit is cleared in MAster code as soon as I shift out SPDR register from master to receive byte which is coming from the slave.

#define spi_data_reg SPDR     
//Naster read byte function
    uint8_t MA_SPI0_read_byte()
    {    
        spi_port &= ~(1<<SS);
        spi_data_reg = 0;
        while(!(SPSR & (1<<SPIF)));                  //Wait until transmission complete
        return(spi_data_reg);                                 //Return received data
       spi_port |= (1<<SS);
    }
//Slave send byte function
void SL_SPI0_send_byte(uint8_t data)
{
    spi_data_direc=(1&lt;&lt;MISO);   //MISO as OUTPUT
    spi_data_reg = data;
    while(!(SPSR &amp;(1&lt;&lt;SPIF)));
}