: bin>number base @ >r 2 base ! >number r> base ! ;

: bin-emit 
  0. bl word count over >r bin>number drop 
  swap drop
  r> > if 
    emit 0 
  else drop -1 endif ;

: bin2asc begin bin-emit until ;

: binary2ascii 
  begin
    0. bl word count over >r bin>number drop 
    swap drop
    r> > while 
      emit
  repeat ;

bin2asc 01001000 01100101 01101100 01101100 01101111