@begin: scope:[]  from
  [0] phi()
  to:@1
@1: scope:[]  from @begin
  [1] phi()
  [2] call main 
  to:@end
@end: scope:[]  from @1
  [3] phi()

(void()) main()
main: scope:[main]  from @1
  [4] phi()
  [5] call output 
  to:main::@return
main::@return: scope:[main]  from main
  [6] return 
  to:@return

(void()) output((dword) output::dw)
output: scope:[output]  from main
  [7] *((const dword*) screen) ← (const dword) main::dw
  to:output::@return
output::@return: scope:[output]  from output
  [8] return 
  to:@return
