SPI INT FLAG not changing value

I can't seem to access the SPI INT FLAG.  I would expect this flag to be a "1" after I send data through the SPI, and I would expect this flag to reset "0" after I read the SPI RX BUFF as per APP Note SPRU059D.  Every time I look at the values of these resigeters they remain unchanged.  I am able to communicate via the SPI but I can't seem to get the registers to update correctly.  My overall goal is to get the SPI to genereate an interrupt to the CPU, but would like to use the flag as a trigger point for some other code.  Here is the code that I am using to try and read the SPI INT FLAG.  Thanks

interrupt void  XINT1_ISR(void)
{
  Uint16 spiaflag;
  Uint16 rdata;
  Uint16 rxovrn;
  long      i;
    // Insert ISR Code here

  // To receive more interrupts from this PIE group, acknowledge this interrupt
  PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;

SpiaRegs.SPITXBUF = 0xAA00;
//Wait till rx is complete
while(SpiaRegs.SPIFFRX.bit.RXFFST !=1) { }
rdata = SpiaRegs.SPIRXBUF;
SpiaRegs.SPITXBUF = 0xFA00;
rxovrn  = SpiaRegs.SPISTS.bit.OVERRUN_FLAG;

  while (count != 5)                                         
  {                                                           
 GpioDataRegs.GPBTOGGLE.bit.GPIO34 = 1;  // Toggle the pin  
 for (i = 0; i < 2000000; i++) {}
 count++;                                                                                                       
  }                                                           
                                                              
count = 0; 
spiaflag = SpiaRegs.SPISTS.bit.INT_FLAG;                                                
rdata = SpiaRegs.SPIRXBUF;
                                                         

rxovrn  = SpiaRegs.SPISTS.bit.OVERRUN_FLAG;

                                                                
}