1. A method for decoding comprising the steps of: (A) generating a plurality of first precision state metrics for a decoder trellis in response to a plurality of first precision branch metrics; (B) generating a plurality of second precision state metrics for a selected subset of said first precision state metrics in response to a plurality of second precision branch metrics; (C) replacing said selected subset of first precision state metrics with said second precision state metrics; and (D) storing said first precision state metrics and said second precision state metrics.