67 lines
2.3 KiB
C
67 lines
2.3 KiB
C
/*
|
|
* Copyright (c) 2005, Swedish Institute of Computer Science
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the Institute nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* This file is part of the Contiki operating system.
|
|
*
|
|
* @(#)$Id: rand.c,v 1.2 2006/11/17 13:05:34 bg- Exp $
|
|
*/
|
|
#include "rand.h"
|
|
|
|
/*
|
|
* Minimal standard random number generator.
|
|
*
|
|
* Simple crappy ANSI C compatible random number generator that is
|
|
* good enough for us!
|
|
*
|
|
* Park, S.K. and K.W. Miller, 1988;
|
|
* Random Number Generators: Good Ones are Hard to Find,
|
|
* Comm. of the ACM, V. 31. No. 10, pp 1192-1201
|
|
*/
|
|
|
|
/*
|
|
* When possible, keep rand_state across reboots.
|
|
*/
|
|
#ifdef __GNUC__
|
|
unsigned long rand_state __attribute__((section(".noinit")));
|
|
#else
|
|
unsigned long rand_state = 123459876ul;
|
|
#endif
|
|
|
|
int
|
|
rand()
|
|
{
|
|
rand_state = (16807*rand_state) % 2147483647ul;
|
|
return rand_state & RAND_MAX;
|
|
}
|
|
|
|
void
|
|
srand(unsigned int seed)
|
|
{
|
|
rand_state = seed;
|
|
}
|