2Bit Branch Predictor (saturation counter)

[greatgamer34]

So its just an down/up 2 bit counter with edge protection. This is also called a saturation counter, IE) when decrementing and at state 00 it will remain at state 00 instead of decrementing to 11; when incrementing at state 11 it will remain at state 11 instead of incrementing to 00. The MSB is the BP's prediction(1=take, 0 =dont take), the LSB is the last outcome of the CPU(did it take the branch or not?; 1 = taken, 0 = did not take). The down/up control line comes from the result of the branch after the result is found(1 clock cycle later).