PLL45XX_PDIV_MASK
pdiv = (pll_con >> PLL45XX_PDIV_SHIFT) & PLL45XX_PDIV_MASK;
old_pdiv = (pll_con0 >> PLL45XX_PDIV_SHIFT) & PLL45XX_PDIV_MASK;
(PLL45XX_PDIV_MASK << PLL45XX_PDIV_SHIFT) |