random.c revision 199767f8919635c4928607450d9e0abb932109ce
199767f8919635c4928607450d9e0abb932109ceToomas Soome * Copyright (c) 1992, 1993
199767f8919635c4928607450d9e0abb932109ceToomas Soome * The Regents of the University of California. All rights reserved.
199767f8919635c4928607450d9e0abb932109ceToomas Soome * Redistribution and use in source and binary forms, with or without
199767f8919635c4928607450d9e0abb932109ceToomas Soome * modification, are permitted provided that the following conditions
199767f8919635c4928607450d9e0abb932109ceToomas Soome * 1. Redistributions of source code must retain the above copyright
199767f8919635c4928607450d9e0abb932109ceToomas Soome * notice, this list of conditions and the following disclaimer.
199767f8919635c4928607450d9e0abb932109ceToomas Soome * 2. Redistributions in binary form must reproduce the above copyright
199767f8919635c4928607450d9e0abb932109ceToomas Soome * notice, this list of conditions and the following disclaimer in the
199767f8919635c4928607450d9e0abb932109ceToomas Soome * documentation and/or other materials provided with the distribution.
199767f8919635c4928607450d9e0abb932109ceToomas Soome * 4. Neither the name of the University nor the names of its contributors
199767f8919635c4928607450d9e0abb932109ceToomas Soome * may be used to endorse or promote products derived from this software
199767f8919635c4928607450d9e0abb932109ceToomas Soome * without specific prior written permission.
199767f8919635c4928607450d9e0abb932109ceToomas Soome * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
199767f8919635c4928607450d9e0abb932109ceToomas Soome * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
199767f8919635c4928607450d9e0abb932109ceToomas Soome * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
199767f8919635c4928607450d9e0abb932109ceToomas Soome * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
199767f8919635c4928607450d9e0abb932109ceToomas Soome * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
199767f8919635c4928607450d9e0abb932109ceToomas Soome * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
199767f8919635c4928607450d9e0abb932109ceToomas Soome * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
199767f8919635c4928607450d9e0abb932109ceToomas Soome * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
199767f8919635c4928607450d9e0abb932109ceToomas Soome * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
199767f8919635c4928607450d9e0abb932109ceToomas Soome * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
199767f8919635c4928607450d9e0abb932109ceToomas Soome * SUCH DAMAGE.
199767f8919635c4928607450d9e0abb932109ceToomas Soome * @(#)random.c 8.1 (Berkeley) 6/10/93
199767f8919635c4928607450d9e0abb932109ceToomas Soome * Pseudo-random number generator for randomizing the profiling clock,
199767f8919635c4928607450d9e0abb932109ceToomas Soome * and whatever else we might use it for. The result is uniform on
199767f8919635c4928607450d9e0abb932109ceToomas Soome * [0, 2^31 - 1].
199767f8919635c4928607450d9e0abb932109ceToomas Soome * Compute x[n + 1] = (7^5 * x[n]) mod (2^31 - 1).
199767f8919635c4928607450d9e0abb932109ceToomas Soome * From "Random number generators: good ones are hard to find",
199767f8919635c4928607450d9e0abb932109ceToomas Soome * Park and Miller, Communications of the ACM, vol. 31, no. 10,
199767f8919635c4928607450d9e0abb932109ceToomas Soome * October 1988, p. 1195.
199767f8919635c4928607450d9e0abb932109ceToomas Soome t += 0x7fffffff;