code: def _translate_stm(self, oprnd1, oprnd2, oprnd3):
          
          assert oprnd1.size and oprnd3.size
          assert oprnd3.size == self._address_size
  
          op1_var = self._translate_src_oprnd(oprnd1)
          op3_var = self._translate_src_oprnd(oprnd3)
  
          for i in range(0, oprnd1.size, 8):
              self._mem_curr[op3_var + i//8] = smtfunction.extract(op1_var, i, 8)
  
          # Memory versioning.
          self._mem_instance += 1
  
          mem_old = self._mem_curr
          mem_new = self.make_array(self._address_size, "MEM_{}".format(self._mem_instance))
  
          self._mem_curr = mem_new
  
          return [mem_new == mem_old]
docs: Return a formula representation of a STM instruction.