7 January 2017

HCCS Forth has no PICK, no semantics for instantiating an infinite DO loop, and will not allow a word to wrap at 80 columns.

Extended fig-FORTH [ Atari 8-bits ]
G.R. Gaukel's 6509.FORTH [ C= B128/256 ]

CELLS is 2 *.

IPC FORTH [ HP Integral PC ]

CELLS is 4 *.

32767 CONSTANT MAXINT
: CELLS 2* ;
: #PRIME@ 2 + CELLS + ;
: #PRIME >R DUP R> #PRIME@ @ ;
: #PRIMES DUP 1 CELLS + @ ;
: #PRIMES++ #PRIMES 1+ OVER 1 CELLS + ! ;
: MAXPRIMES DUP @ ;
: NOTPRIME DROP 0 ;
: DIVIDES? MOD 0= ;
: INITIALIZE DUP >R HERE DUP R> 2 + CELLS ALLOT ROT SWAP ! 0 OVER 1 CELLS + ! ;
: ISPRIME! DUP . CR OVER #PRIMES #PRIME@ ! #PRIMES++ ;
: ISPRIME? OVER #PRIMES 0 DO I #PRIME >R OVER R> DIVIDES?
   IF NOTPRIME LEAVE THEN LOOP ;
: PRIMES DECIMAL INITIALIZE CR 2 ISPRIME! MAXINT 3 DO I ISPRIME? IF ISPRIME!
   ELSE DROP THEN MAXPRIMES >R #PRIMES R> = IF LEAVE THEN LOOP ;