@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()
  to:main::@1
main::@1: scope:[main]  from main main::@2
  [5] (byte) main::key#0 ← *((const byte*) RASTER)
  [6] if((byte) main::key#0>=(byte) $20+(byte) 1) goto main::@2
  to:main::@3
main::@3: scope:[main]  from main::@1
  [7] if((byte) main::key#0>=(byte) $40) goto main::@4
  to:main::@2
main::@4: scope:[main]  from main::@3
  [8] phi()
  to:main::@2
main::@2: scope:[main]  from main::@1 main::@3 main::@4
  [9] (byte) main::key#2 ← phi( main::@4/(byte) main::key#0 main::@1/(byte) 0 main::@3/(byte) 0 )
  [10] *((const byte*) SCREEN) ← (byte) main::key#2
  to:main::@1
