code: def UXTH(self, params):
          
          Ra, Rb = self.get_two_parameters(r'\s*([^\s,]*),\s*([^\s,]*)(,\s*[^\s,]*)*\s*', params)
  
          self.check_arguments(low_registers=(Ra, Rb))
  
          def UXTH_func():
              self.register[Ra] = (self.register[Rb] & 0xFFFF)
  
          return UXTH_func
docs: UTXH Ra, Rb
  
          Zero extend the half word in Rb and store the result in Ra