message: RV5S: Do not forward writes to register 0 (Read-only)
diff: @@ -17,7 +17,9 @@ public:
  ForwardingUnit(std::string name, SimComponent* parent) : Component(name, parent) {
  alu_reg1_forwarding_ctrl << [=] {
  const auto idx = id_reg1_idx.uValue();
  - if (idx == mem_reg_wr_idx.uValue() && mem_reg_wr_en.uValue()) {
  + if (idx == 0) {
  + return ForwardingSrc::IdStage;
  + } else if (idx == mem_reg_wr_idx.uValue() && mem_reg_wr_en.uValue()) {
  return ForwardingSrc::MemStage;
  } else if (idx == wb_reg_wr_idx.uValue() && wb_reg_wr_en.uValue()) {
  return ForwardingSrc::WbStage;
  @@ -28,7 +30,9 @@ public:
  alu_reg2_forwarding_ctrl << [=] {
  const auto idx = id_reg2_idx.uValue();
  - if (idx == mem_reg_wr_idx.uValue() && mem_reg_wr_en.uValue()) {
  + if (idx == 0) {
  + return ForwardingSrc::IdStage;
  + } else if (idx == mem_reg_wr_idx.uValue() && mem_reg_wr_en.uValue()) {
  return ForwardingSrc::MemStage;
  } else if (idx == wb_reg_wr_idx.uValue() && wb_reg_wr_en.uValue()) {
  return ForwardingSrc::WbStage;
  