Help needed

Could someone explain me the program of MMIO? Plz

Why have they chosen these values for
STOP_TIMER1_MASK 0x0010
PRD_VALUE 0xffff
TDDR_VALUE 0x000f
TRB_MASK 0x0020
TINT1_ENABLE_MASK 0x0080

I did'nt understand the reason behind choosing te vlaues for stop timer mask and so on..

Plz help me in this regard.

Thanks

Please go through section 8.4 of C:/ti/docs/pdf/spru131g.pdf