Upon appeal by the people the reviewing court may review any question of law involved in any ruling affecting the judgment or order appealed from, without exception having been taken in the trial court. Upon an appeal by a defendant the court may, without exception having been taken in the trial court, review any question of law involved in any ruling, order, instruction, or thing whatsoever said or done at the trial or prior to or after judgment, which thing was said or done after objection made in and considered by the trial court and which affected the substantial rights of the defendant. The court may also review any instruction given, refused or modified, even though no objection was made thereto in the trial court if the substantial rights of the defendant were affected thereby. The reviewing court may reverse, affirm or modify the judgment or order appealed from, and may set aside, affirm or modify any or all of the proceedings subsequent to, or dependent upon, such judgment or order, and may, if proper, order a new trial. If a new trial is ordered upon appeal, it must be had in the court from which the appeal is taken.