frontend: add a signal to know if a prediction was correct

Signed-off-by: Alban Gruin <alban.gruin@irit.fr>

src/frontend/frontend.sv

@@ -98,7 +98,7 @@ module frontend import ariane_pkg::*; #(
     ras_t            ras_predict;
 
     // branch-predict update
-    logic            is_mispredict;
+    logic            is_correct_predict, is_mispredict;
     logic            ras_push, ras_pop;
     logic [riscv::VLEN-1:0]     ras_update;
 
@@ -233,6 +233,7 @@ module frontend import ariane_pkg::*; #(
       // contains a valid prediction.
       for (int i = 0; i < INSTR_PER_FETCH; i++) bp_valid |= ((cf_type[i] != NoCF & cf_type[i] != Return) | ((cf_type[i] == Return) & ras_predict.valid));
     end
+    assign is_correct_predict = resolved_branch_i.valid & !(resolved_branch_i.is_mispredict);
     assign is_mispredict = resolved_branch_i.valid & resolved_branch_i.is_mispredict;
 
     // Cache interface