1. A method for calculating forward and reverse metrics required for performing an output calculation to determine binary states of received signals, comprising the steps of: (a) performing the forward metric calculations in two stages, wherein a first group of the forward metric calculations are calculated in a first stage followed by a second group of forward metric calculations being calculated in a second stage; (b) reading the forward metrics calculated during the first stage from memory for use with reverse metric values to perform the output calculation; (c) performing the reverse metric calculations in the second stage, following the first stage; (d) performing the second half of forward metric calculations as said reverse calculations are being performed; (e) storing each of the forward metric calculations performed in the first stage; and (f) writing each forward metric calculated during the second stage into a memory location that a forward metric calculated during the first stage is being read out for use in an output calculation.