EightBall/sieve4.8b

' Sieve of Eratosthenes

byte A[400] = 1
call doall(20)
end

sub doall(word nr)
  word n = nr * nr
  pr.msg "Sieve of Eratosthenes ..."
  pr.msg "nr is "; pr.dec nr; pr.nl
  call sieve(n, nr)
  call printresults(n)
  return 0
endsub

sub sieve(word n, word nr)
  pr.msg "Sieve"
  word i = 0; word j = 0
  for i = 2 : (nr - 1)
    if A[i]
      j = i * i
      while (j < n)
        A[j] = 0
        j = j + i
      endwhile
    endif
  endfor
  return 0
endsub

sub printresults(word n)
  word i = 0
  for i = 2 : (n - 1)
    if A[i]
      if i > 2
        pr.msg ", "
      endif
      pr.dec i
    endif
  endfor
  pr.msg "."
  pr.nl
  return 0
endsub