anchor.diff:     // INTERFACE
   
      method Action start(Addr initial_pc) if (!cpu_enabled);
  -      pc          <= initial_pc;
  +      rg_FetchPC  <= initial_pc;
         pcEpoch     <= initial_pc;
         cpu_enabled <= True;
      endmethod
  
positive.code:    // Instruction fetch
     (* fire_when_enabled *)
     rule rl_fetch(cpu_enabled);
        let next_pc = fromMaybe(fromMaybe(pc, rw_nxtPC.wget), rw_jmpPC.wget);
        if (cfg_verbose > 1) $display("[%7d] rl_fetch : Read instruction pc = 0x%08h", csr_cycle, next_pc);
        memory.imem_req(next_pc);
        rg_f2d <= tagged Valid next_pc;
        pc <= next_pc;
     endrule
  
     // ----------------------------------------------------------------
  
negative.code:    Reg#(Bool)  cpu_enabled <- mkReg(False);
  
     // Program counter
     Reg#(Addr)     rg_FetchPC  <- mkRegU;
     RWire#(Addr)   rw_nxtPC    <- mkRWire;
     RWire#(Addr)   rw_jmpPC    <- mkUnsafeRWire;
     Reg#(Word)     pcEpoch     <- mkConfigRegU;
  
     // General Purpose Registers
     RegFile#(RegName, Word) rf_GPRs  <- mkRegFileWCF(0, ~0);
  