code: def instruction_NEG_memory(self, opcode, ea, m):
          
          if opcode == 0x0 and ea == 0x0 and m == 0x0:
              self._wrong_NEG += 1
              if self._wrong_NEG > 10:
                  raise RuntimeError("Wrong PC ???")
          else:
              self._wrong_NEG = 0
  
          r = m * -1 # same as: r = ~m + 1
  
  #        log.debug("$%04x NEG $%02x from %04x to $%02x" % (
  #             self.program_counter, m, ea, r,
  #         ))
          self.clear_NZVC()
          self.update_NZVC_8(0, m, r)
          return ea, r & 0xff
docs: Negate memory