CCS/LAUNCHXL-F280049C: QUESTIONS ON SPI EXAMPLE CODE

Part Number: LAUNCHXL-F280049C
Other Parts Discussed in Thread: C2000WARE

Tool/software: Code Composer Studio

Hi all:

     I am now trying to modify the SPI example code which is "C2000_LAUNCHPAID\software_install\C2000Ware_3_02_00_00\driverlib\f28004x\examples\spi\spi_ex4_eeprom.c".

     I don't very undestand these three functions which are "readStatusRegister()" and "SPI_writeDataBlockingNonFIFO", "SPI_readDataBlockingNonFIFO".

     What do these functions for?  If I don't use these functions, what kinds of errors will occur? Do the "readStatusRegister()" just for checking the SPI bus is busy or not? or check the INT_FLAG?

Also, I don't really understand these marcons for(see below). I don't find them in datasheet.

#define RDSR                        0x0500
#define READ                        0x0300
#define WRITE                       0x0200
#define WREN                        0x0600
#define WRDI                        0x0400
#define WRSR                        0x0100

uint16_t readStatusRegister(void)
{
    uint16_t temp;

    //
    // Pull chip select low.
    //
    CSCON_TXLOW;

    //
    // Send RDSR opcode
    //
    SPI_writeDataBlockingNonFIFO(SPIA_BASE, RDSR);

    //
    // Dummy read to clear INT_FLAG.
    // spi read rxbuf will clear INT_FLAG
    temp = SPI_readDataBlockingNonFIFO(SPIA_BASE);

    //
    // Send dummy data to receive the status.
    //
    SPI_writeDataBlockingNonFIFO(SPIA_BASE, 0x0000);

    //
    // Read status register.
    //
    temp = SPI_readDataBlockingNonFIFO(SPIA_BASE);

    //
    // Pull chip select high.
    //
    CSCON_TXHIGH;

    //
    // Read the status from the receive buffer
    //
    return(temp);
}

     If I just want communicate peripherals through SPI with non-FIFO, what should I modify in example code?