anchor.diff:  
   # send a sequence item
   seq_item_create vip_tr tr
  -seq_item_rand tr
   seq_item_set_fields tr chr='hff
   seqr_execute_item env.vip.sqr tr
   
  
positive.code: wr_regfld regmodel.TxStatus.TxEn 0
  rd_regfld regmodel.TxStatus.TxEn
  
  # load command file
  history save demo1
  read demo1
  
  # continue to demo sequence commands
  continue
  
negative.code: # house keeping functions
  help
  run 10ns
  run 20ns
  pause
  call debug_prompt
  history
  repeat 1
  history clear
  history
  
  # register access
  rd_addr 0
  rd_addr 4 
  
  # load command file
  history save demo1
  read demo1
  
  wr_addr 4 1
  rd_addr 4 
  rd_reg regmodel.IntMask 
  wr_reg regmodel.IntMask 0
  rd_reg regmodel.IntMask 
  