(*
 * LANGUAGE    : ANS Forth
 * PROJECT     : Forth Environments
 * DESCRIPTION : The Famous Sieve of Eratosthanes, using bits
 * CATEGORY    : Benchmarks
 * AUTHOR      : Marcel Hendrix
 * LAST CHANGE : Monday, June 04, 2001 11:54 PM, MHX
 *)


	NEEDS -miscutil

	REVISION -bit-sieve "ÄÄÄ SIEVE benchmark     Version 1.01 ÄÄÄ"


#1000 =: #times
#8192 =: size

CREATE flags	size 8 / CHARS ALLOT

: DO-PRIME	flags [ size 8 / ] LITERAL %11111111 FILL
		0  size 0 DO flags I 
			     BIT? IF I 2*  3 +
				     DUP  I +
			  	     BEGIN  DUP size 
				  U< WHILE  flags OVER BIT-RESET 
					    OVER +
				     REPEAT 
				     2DROP 1+
			       ENDIF
			LOOP ;

: PRIMES	CR #times DEC. ." iterations."  TIMER-RESET
		0 #times 0 DO  DROP  DO-PRIME  LOOP
		MS? SWAP CR .  ." primes found, " DEC. ." ms elapsed." ;

:ABOUT		CR ." Sieve (" #times 0 .R ."  iterations)"
		CR ." Enter PRIMES to run the (bit test) benchmark." 
		CR ." On AMD Athlon this is only 10% slower than sieve.frt ." ;

		.ABOUT -bit-sieve CR

				(* End *)