void main()
main: scope:[main]  from
  [0] phi()
  to:main::@1
main::@1: scope:[main]  from main main::@1
  [1] main::w#2 = phi( main/0, main::@1/main::w#1 )
  [2] main::$0 = byte0  main::w#2
  [3] *main::SCREEN = main::$0
  [4] main::$1 = byte1  main::w#2
  [5] *(main::SCREEN+1) = main::$1
  [6] main::w#1 = ++ main::w#2
  [7] if(main::w#1!=0) goto main::@1
  to:main::@2
main::@2: scope:[main]  from main::@1 main::@2
  [8] main::sw#2 = phi( main::@1/-$7fff, main::@2/main::sw#1 )
  [9] main::$3 = byte0  main::sw#2
  [10] *(main::SCREEN+3) = main::$3
  [11] main::$4 = byte1  main::sw#2
  [12] *(main::SCREEN+4) = main::$4
  [13] main::sw#1 = ++ main::sw#2
  [14] if(main::sw#1!=$7fff) goto main::@2
  to:main::@return
main::@return: scope:[main]  from main::@2
  [15] return 
  to:@return