Is a prosecutor required to provide impeachment evidence intended to be used during cross-examination of defense witnesses?

Penal Code section 1054.1 provides in relevant part: "The prosecuting attorney shall disclose to the defendant or his or her attorney all of the following materials and information, if it is in the possession of the prosecuting attorney or if the prosecuting attorney knows it to be in the possession of the investigating agencies: [] . . . [] (e) Any exculpatory evidence. [] (f) Relevant written or recorded statements of witnesses or reports of the statements of witnesses whom the prosecutor intends to call at the trial . . ." (Pen. Code, 1054.1, subds. (e), (f).) However, there is no requirement that the prosecutor provide impeachment evidence intended to be used during cross-examination of defense witnesses. In fact, such disclosure has been found not to fall within the discovery obligations of the prosecution. (People v. Tillis (1998) 18 Cal.4th 284, 292-293.)