old_contents: import simuvex
  from simuvex.s_type import SimTypeInt
  
  ######################################
  # getchar
  ######################################
  
  class getchar(simuvex.SimProcedure):
      def run(self):
          self.return_type = SimTypeInt(32, True)
          data = self.state.posix.read(0,1)
          data = data.zero_extend(self.state.arch.bits-data.size())
          return data
  
new_contents: import simuvex
  from simuvex.s_type import SimTypeInt
  
  ######################################
  # getchar
  ######################################
  
  class getchar(simuvex.SimProcedure):
      def run(self):
          self.return_type = SimTypeInt(32, True)
          data = self.state.posix.read_from(0,1)
          data = data.zero_extend(self.state.arch.bits-data.size())
          return data
  
subject: Update getchar simprocedure to use the new read calling convention