public void scaleDownTenDestructive(short tenScale) {
    this.mag.scaleDownTenDestructive(tenScale);
    if (this.mag.isZero() && this.negative) {
      this.negative = false;
    }
  }
Scale down the value for 10**tenScale (this := this / 10**tenScale). This
method rounds-up, eg 44/10=4, 45/10=5. This version is destructive, meaning
it modifies this object.

@param tenScale
         scaling. must be positive
common/src/java/org/apache/hadoop/hive/common/type/SignedInt128.java