ID_AA64DFR0_WRPs_SHIFT
nwtpts = ID_AA64DFR0_WRPs_VAL(dfr0) >> ID_AA64DFR0_WRPs_SHIFT;
#define ID_AA64DFR0_WRPs_MASK (UL(0xf) << ID_AA64DFR0_WRPs_SHIFT)
((((x) >> ID_AA64DFR0_WRPs_SHIFT) & 0xf) + 1)