code: def __execute_stm(self, instr):
          
          assert instr.operands[0].size in [8, 16, 32, 64, 128, 256]
          assert instr.operands[2].size == self.__mem.address_size
  
          op0_val = self.read_operand(instr.operands[0])  # Data.
          op2_val = self.read_operand(instr.operands[2])  # Memory address.
  
          op0_size = instr.operands[0].size
  
          self.write_memory(op2_val, op0_size // 8, op0_val)
  
          return None
docs: Execute STM instruction.