Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!pilchuck!amc-gw!thebes!polari!tm
From: tm@polari.UUCP (Toshi Morita)
Newsgroups: comp.binaries.apple2
Subject: SIEVE
Keywords: Qforth
Message-ID: <2305@polari.UUCP>
Date: 5 Aug 90 00:27:39 GMT
Distribution: na
Organization: Seattle Online Public Unix (206) 328-4944
Lines: 45


Sieve demo for QForth.



10000 constant size

create flags size 1+ allot

variable count
variable prime
variable ref

: sieve

  cr ." Sieve x 10... " cr

  10 0
    do

      0 count !
      flags size 1+ 1 fill

      size 1+ 1
        do 
          flags i + c@
            if
              i dup + 2+ 1+ prime !
              i prime @ + ref !
                begin
                  ref @ size <
                while
                  0 flags ref @ + c!
                  ref @ prime @ + ref !
                repeat
              count @ 1+ count !
            else
            then
        loop

   loop

  ." ...done. " cr count ? ." primes. "

;