GetPLLReg
SetPLLReg(index, (GetPLLReg(index) & ~mask) | (value & mask));
uint32 mclkCntl = GetPLLReg(R128_MCLK_CNTL);
while (GetPLLReg(R128_PPLL_REF_DIV) & R128_PPLL_ATOMIC_UPDATE_R)