xnu-6153.11.26.tar.gz

[apple/xnu.git] / bsd / libkern / random.c

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/*-
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 *	@(#)random.c	8.1 (Berkeley) 6/10/93
 */

#include <sys/types.h>
#include <sys/random.h>
#include <libkern/libkern.h>
#include <dev/random/randomdev.h>

/*
 * Pseudo-random number generator for randomizing the profiling clock,
 * and whatever else we might use it for.  The result is uniform on
 * [0, 2^31 - 1].
 */
u_int32_t
random(void)
{
	/* Zero all but bottom 31 bits, also works for 64-bit longs */
	u_int32_t mask = (u_int32_t)-1 >> ((sizeof(u_int32_t) * 8) - 31);
	return mask & RandomULong();
}