Speculative tomasulo, branch in the issue phase

I had confusions on SPeculative tomasulo; now, which I know the correct answer for.

1) If one branch is in issue phase in cycle (C) should we suspend other later instruction from issuing in the cycle cycle ?

Ans:Yes. So, if there is a branch instruction in a cycle (say 10) issue no other later instruction in the 10th cycle.

2) When a reservation station becomes  free?

Ans: It becomes free after writing the result to CDB. Not after issuing the instruction in the functional unit.

Advertisement