code: def read_register(self, register):
          
          self._publish('will_read_register', register)
          value = self._regfile.read(register)
          self._publish('did_read_register', register, value)
          return value
docs: Dynamic interface for reading cpu registers
  
          :param str register: register name (as listed in `self.all_registers`)
          :return: register value
          :rtype: int or long or Expression