Added counting code for return instructions

src_Core/CPU/Core.bsv

@@ -309,6 +309,10 @@ module mkCore#(CoreId coreId)(Core);
     for(Integer i = 0; i < valueof(SupSize); i=i+1) begin
         bags[i] <- mkSmallBag;
     end
+    Vector#(SupSize, Bag#(16, CapMem, CapMem)) returnBags;
+    for(Integer i = 0; i < valueof(SupSize); i=i+1) begin
+        returnBags[i] <- mkSmallBag;
+    end
 
     // We have two scoreboards: one conservative and other aggressive
     // - Aggressive sb is checked at rename stage, so inst after rename may be issued early
@@ -436,6 +440,13 @@ module mkCore#(CoreId coreId)(Core);
                     end
                     return ret;
                 endmethod
+                method Bool checkReturnTarget(CapMem ppc);
+                    Bool ret = False;
+                    for(Integer j = 0; j < valueof(SupSize); j=j+1) begin
+                        ret = ret || returnBags[j].isMember(ppc).v;
+                    end
+                    return ret;
+                endmethod
             endinterface);
             aluExe[i] <- mkAluExePipeline(aluExeInput);
             // truly call fetch method to train branch predictor
@@ -696,6 +707,14 @@ module mkCore#(CoreId coreId)(Core);
             end
         endmethod
 
+        method Action updateReturnTargets(Vector#(SupSize, Maybe#(CapMem)) returnTargets);
+            for(Integer i = 0; i < valueof(SupSize); i=i+1) begin
+                if(returnTargets[i] matches tagged Valid .retTar) begin
+                    returnBags[i].insert(retTar, retTar);
+                end
+            end
+        endmethod
+
 `ifdef INCLUDE_TANDEM_VERIF
        interface v_to_TV = map (toPut, v_f_to_TV);
 `endif

src_Core/RISCY_OOO/procs/RV64G_OOO/AluExePipeline.bsv

@@ -198,6 +198,8 @@ interface AluExeInput;
 
     // check previous branch targets
     method Bool checkTarget(CapMem ppc);
+    // check (previous) return targets
+    method Bool checkReturnTarget(CapMem ppc);
 endinterface
 
 interface AluExePipeline;
@@ -294,6 +296,7 @@ module mkAluExePipeline#(AluExeInput inIfc)(AluExePipeline);
         let ppc = inIfc.rob_getPredPC(x.tag);
         let orig_inst = inIfc.rob_getOrig_Inst (x.tag);
 
+        // TODO: split into Br, jumps, and rets
 `ifdef PERFORMANCE_MONITORING
         if(x.dInst.iType == Br || x.dInst.iType == Jr || x.dInst.iType == CJALR) begin
             $display("BRANCH pc = ", fshow(pc), ", ppc = ", fshow(ppc));

src_Core/RISCY_OOO/procs/RV64G_OOO/CommitStage.bsv

@@ -134,6 +134,8 @@ interface CommitInput;
 
     // update branch targets
     method Action updateTargets(Vector#(SupSize, Maybe#(CapMem)) targets);
+    // update return targets
+    method Action updateReturnTargets(Vector#(SupSize, Maybe#(CapMem)) returnTargets);
 
 `ifdef INCLUDE_TANDEM_VERIF
     interface Vector #(SupSize, Put #(Trace_Data2)) v_to_TV;
@@ -1093,9 +1095,12 @@ module mkCommitStage#(CommitInput inIfc)(CommitStage);
 
         // update targets vector
         Vector#(SupSize, Maybe#(CapMem)) targets;
+        // update return targets vector
+        Vector#(SupSize, Maybe#(CapMem)) returnTargets;
         // compute what actions to take
         for(Integer i = 0; i < valueof(SupSize); i = i+1) begin
             Maybe#(CapMem) tar = tagged Invalid;
+            Maybe#(CapMem) retTar = tagged Invalid;
             if(!stop && rob.deqPort[i].canDeq) begin
                 let x = rob.deqPort[i].deq_data;
                 let inst_tag = rob.deqPort[i].getDeqInstTag;
@@ -1139,6 +1144,20 @@ module mkCommitStage#(CommitInput inIfc)(CommitStage);
                     // inst can be committed, deq it
                     rob.deqPort[i].deq;
 
+                    // return address stack link reg is x1 or x5
+                    function Bool linkedR(Maybe#(ArchRIndx) register);
+                        Bool res = False;
+                        if (register matches tagged Valid .r &&& (r == tagged Gpr 1 || r == tagged Gpr 5)) begin
+                           res = True;
+                        end
+                        return res;
+                    endfunction
+
+                    // update return target
+                    if((x.iType == J || x.iType == CJAL) && linkedR(x.dst)) begin
+                        retTar = tagged Valid x.ppc_vaddr_csrData.PPC;
+                    end
+
                     // update target
                     if(x.iType == CJALR || x.iType == Jr) begin
                         tar = tagged Valid x.ppc_vaddr_csrData.PPC;
@@ -1220,6 +1239,7 @@ module mkCommitStage#(CommitInput inIfc)(CommitStage);
                 end
             end
             targets[i] = tar;
+            returnTargets[i] = retTar;
         end
         rg_serial_num <= rg_serial_num + instret;
 
@@ -1285,6 +1305,7 @@ module mkCommitStage#(CommitInput inIfc)(CommitStage);
 `endif
 
         inIfc.updateTargets(targets);
+        inIfc.updateReturnTargets(returnTargets);
 
 `ifdef RVFI
         rvfiQ.enq(rvfis);