PERF_REG_S390_FP0
if (idx >= PERF_REG_S390_FP0 && idx <= PERF_REG_S390_FP15) {
idx -= PERF_REG_S390_FP0;
[PERF_REG_S390_FP0] = 16,
case PERF_REG_S390_FP0: