(a) If a defendant upon arraignment or prior to trial pleads guilty, the court, without the intervention of a jury, shall determine the degree of the offense and fix the punishment therefor the same as a jury might fix or impose it if the case were being tried by a jury, unless, in the discretion of the trial judge, a jury should be impaneled to determine the degree of the offense or to fix the punishment therefor or unless the defendant at the time of entering such plea demands a jury in writing. The court shall not in any event, however, impose capital punishment without the intervention of a jury.

(b) Whenever, in the discretion of the trial judge, a jury should be impaneled or a jury is demanded, in the manner and at the time prescribed in subsection (a) of this section, no special venire need be drawn, but the court must cause the punishment to be determined by a jury, except where the punishment is required by law to be fixed by the court.

(c) The court may in all cases in which a plea of guilty is entered cause witnesses to be examined to ascertain the character of the offense.

(d) Nothing contained in this section shall be construed as authorizing an accused who has entered a plea of guilty to demand a jury to determine any issue or to fix punishment in regard to any offense unless the right to have a jury determine such issue or to fix the punishment in regard to the offense with which he is charged is granted under some other applicable provisions of law.