2 * Copyright (c) 1992, 1993
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4 * Copyright (c) 2005 Pavel Fedin
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30 * @(#)random.c 8.1 (Berkeley) 6/10/93
33 #include <sys/cdefs.h>
34 #include <sys/types.h>
37 #define NSHUFF 50 /* to drop some "seed -> 1st value" linearity */
39 static u_long randseed
= 937186357; /* after srandom(1), NSHUFF counted */
48 for (i
= 0; i
< NSHUFF
; i
++)
53 * Pseudo-random number generator for randomizing the profiling clock,
54 * and whatever else we might use it for. The result is uniform on
60 register long x
, hi
, lo
, t
;
63 * Compute x[n + 1] = (7^5 * x[n]) mod (2^31 - 1).
64 * From "Random number generators: good ones are hard to find",
65 * Park and Miller, Communications of the ACM, vol. 31, no. 10,
66 * October 1988, p. 1195.
68 /* Can't be initialized with 0, so use another value. */
69 if ((x
= randseed
) == 0)
73 t
= 16807 * lo
- 2836 * hi
;