(a) Where there is no conflict in the evidence and the evidence introduced with all reasonable deductions and inferences therefrom shall demand a verdict of acquittal or "not guilty" as to the entire offense or to some particular count or offense, the court may direct the verdict of acquittal to which the defendant is entitled under the evidence and may allow the trial to proceed only as to the counts or offenses remaining, if any.

(b) The defendant shall be entitled to move for a directed verdict at the close of the evidence offered by the prosecuting attorney or at the close of the case, even if he fails to introduce any evidence at the trial. A defendant who moves for a directed verdict at the close of the evidence offered by the prosecuting attorney may offer evidence in the event that the motion is not granted, without having reserved the right to do so and to the same extent as if the motion had not been made. A motion for a directed verdict which is not granted shall not be deemed to be a waiver of the right to trial by jury. The order of the court granting a motion for a directed verdict of acquittal is effective without any assent of the jury.