2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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34 static const char copyright[] =
35 "@(#) Copyright (c) 1989, 1993\n\
36 The Regents of the University of California. All rights reserved.\n";
41 static char sccsid[] = "@(#)primes.c 8.5 (Berkeley) 5/10/95";
43 static const char rcsid[] =
48 * primes - generate a table of primes between two values
50 * By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
52 * chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
55 * primes [-h] [start [stop]]
57 * Print primes >= start and < stop. If stop is omitted,
58 * the value 4294967295 (2^32-1) is assumed. If start is
59 * omitted, start is read from standard input.
61 * validation check: there are 664579 primes between 0 and 10^7
78 * Eratosthenes sieve table
80 * We only sieve the odd numbers. The base of our sieve windows are always
81 * odd. If the base of table is 1, table[i] represents 2*i-1. After the
82 * sieve, table[i] == 1 if and only if 2*i-1 is prime.
84 * We make TABSIZE large to reduce the overhead of inner loop setup.
86 static char table[TABSIZE]; /* Eratosthenes sieve of odd numbers */
90 static void primes(ubig, ubig);
91 static ubig read_num_buf(void);
92 static void usage(void);
95 main(int argc, char *argv[])
97 ubig start; /* where to start generating */
98 ubig stop; /* don't generate at or above this value */
102 while ((ch = getopt(argc, argv, "h")) != -1)
118 * Convert low and high args. Strtoumax(3) sets errno to
119 * ERANGE if the number is too large, but, if there's
120 * a leading minus sign it returns the negation of the
121 * result of the conversion, which we'd rather disallow.
125 /* Start and stop supplied on the command line. */
126 if (argv[0][0] == '-' || argv[1][0] == '-')
127 errx(1, "negative numbers aren't permitted.");
130 start = strtoumax(argv[0], &p, 0);
132 err(1, "%s", argv[0]);
134 errx(1, "%s: illegal numeric format.", argv[0]);
137 stop = strtoumax(argv[1], &p, 0);
139 err(1, "%s", argv[1]);
141 errx(1, "%s: illegal numeric format.", argv[1]);
143 errx(1, "%s: stop value too large.", argv[1]);
146 /* Start on the command line. */
147 if (argv[0][0] == '-')
148 errx(1, "negative numbers aren't permitted.");
151 start = strtoumax(argv[0], &p, 0);
153 err(1, "%s", argv[0]);
155 errx(1, "%s: illegal numeric format.", argv[0]);
158 start = read_num_buf();
165 errx(1, "start value must be less than stop value.");
172 * This routine returns a number n, where 0 <= n && n <= BIG.
178 char *p, buf[LINE_MAX]; /* > max number of digits. */
181 if (fgets(buf, sizeof(buf), stdin) == NULL) {
186 for (p = buf; isblank(*p); ++p);
187 if (*p == '\n' || *p == '\0')
190 errx(1, "negative numbers aren't permitted.");
192 val = strtoumax(buf, &p, 0);
196 errx(1, "%s: illegal numeric format.", buf);
202 * primes - sieve and print primes from start up to and but not including stop
205 primes(ubig start, ubig stop)
207 char *q; /* sieve spot */
208 ubig factor; /* index and factor */
209 char *tab_lim; /* the limit to sieve on the table */
210 const ubig *p; /* prime table pointer */
211 ubig fact_lim; /* highest prime for current block */
212 ubig mod; /* temp storage for mod */
215 * A number of systems can not convert double values into unsigned
216 * longs when the values are larger than the largest signed value.
217 * We don't have this problem, so we can go all the way to BIG.
230 * be sure that the values are odd, or 2
232 if (start != 2 && (start&0x1) == 0) {
235 if (stop != 2 && (stop&0x1) == 0) {
240 * quick list of primes <= pr_limit
242 if (start <= *pr_limit) {
243 /* skip primes up to the start value */
244 for (p = &prime[0], factor = prime[0];
245 factor < stop && p <= pr_limit; factor = *(++p)) {
246 if (factor >= start) {
247 printf(hflag ? "%" PRIx64 "\n" : "%" PRIu64 "\n", factor);
250 /* return early if we are done */
258 * we shall sieve a bytemap window, note primes and move the window
259 * upward until we pass the stop point
261 while (start < stop) {
263 * factor out 3, 5, 7, 11 and 13
265 /* initial pattern copy */
266 factor = (start%(2*3*5*7*11*13))/2; /* starting copy spot */
267 memcpy(table, &pattern[factor], pattern_size-factor);
268 /* main block pattern copies */
269 for (fact_lim=pattern_size-factor;
270 fact_lim+pattern_size<=TABSIZE; fact_lim+=pattern_size) {
271 memcpy(&table[fact_lim], pattern, pattern_size);
273 /* final block pattern copy */
274 memcpy(&table[fact_lim], pattern, TABSIZE-fact_lim);
277 * sieve for primes 17 and higher
279 /* note highest useful factor and sieve spot */
280 if (stop-start > TABSIZE+TABSIZE) {
281 tab_lim = &table[TABSIZE]; /* sieve it all */
282 fact_lim = sqrt(start+1.0+TABSIZE+TABSIZE);
284 tab_lim = &table[(stop-start)/2]; /* partial sieve */
285 fact_lim = sqrt(stop+1.0);
287 /* sieve for factors >= 17 */
288 factor = 17; /* 17 is first prime to use */
289 p = &prime[7]; /* 19 is next prime, pi(19)=7 */
291 /* determine the factor's initial sieve point */
294 q = &table[(factor-mod)/2];
296 q = &table[mod ? factor-(mod/2) : 0];
298 /* sive for our current factor */
299 for ( ; q < tab_lim; q += factor) {
300 *q = '\0'; /* sieve out a spot */
303 } while (factor <= fact_lim);
306 * print generated primes
308 for (q = table; q < tab_lim; ++q, start+=2) {
310 if (start > SIEVEMAX) {
314 printf(hflag ? "%" PRIx64 "\n" : "%" PRIu64 "\n", start);
323 fprintf(stderr, "usage: primes [-h] [start [stop]]\n");