5505 SPI register read

I am probably missing something simple here.  I am trying to read the received bits in the SPI data register 1.  I can see the correct bits in CCSv5 memory browser SPIDAT1.  When I read the bits from this register, the last two bits always gets set to 0.  So if the SPI receives 0xFFFF, I will read 0xFFFC.  I have tried testing the SPI using a loopback test but constantly read the wrong bits even though I can see the correct bits in the memory browser.  Is there something simple I'm missing?  Mike