bin/gawk/random.c

33  * $FreeBSD: src/lib/libc/stdlib/random.c,v 1.13 2000/01/27 23:06:49 jasone Exp $
38 static const char sccsid[] = "@(#)random.c	8.2 (Berkeley) 5/19/95";
41 #include "random.h"		/* gawk addition */
58 /* For gawk, don't this, use the decl of random() in random.h */
74  * random.c:
76  * An improved random number generation package.  In addition to the standard
80  * then initialized to contain information for random number generation with
85  * information and generates far better random numbers than a linear
97  * The random number generation technique is a linear feedback shift register
104  * influenced by pseudo-random carries out of the lower bits.  The total
125  * state information and generates far better random numbers than a linear
133  * For each of the currently supported random number generators, we have a
135  * many bytes of state info to support this random number generator), a degree
191 /* The random sequences do not vary much with the seed */
212  * could get away with just one pointer, but the code for random() is more
229  * of random(), we remember the first location of the state information, not
249  * The random sequences do not vary much with the seed,
276  * Initialize the random number generator based on the given seed.  If the
300 			(void)random();
348 		 * even to generate a random number, but we do it anyway.
368  * random number generation.  Based on the number of bytes we are given, and
402 		    "random: not enough state (%ld bytes); ignored.\n", n);
480 		    "random: state info corrupted; not changed.\n");
492  * random:
500  * generated, reduced to 31 bits by throwing away the "least random" low bit.
506  * Returns a 31-bit random number.
509 random()
523 		i = (*f >> 1) & 0x7fffffff;	/* chucking least random bit */