/*******************************************************************************
    OpenAirInterface
    Copyright(c) 1999 - 2014 Eurecom

    OpenAirInterface is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.


    OpenAirInterface is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with OpenAirInterface.The full GNU General Public License is
   included in this distribution in the file called "COPYING". If not,
   see <http://www.gnu.org/licenses/>.

  Contact Information
  OpenAirInterface Admin: openair_admin@eurecom.fr
  OpenAirInterface Tech : openair_tech@eurecom.fr
  OpenAirInterface Dev  : openair4g-devel@eurecom.fr

  Address      : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE

 *******************************************************************************/
#ifdef USER_MODE
#include <time.h>
#include <stdlib.h>
#else
#include <asm/io.h>
#include <asm/rtai.h>
#endif
#ifdef RTAI_ENABLED
#include <rtai.h>
#include <rtai_sched.h>
#define time(x) (unsigned int)(rt_get_time_ns())
#endif

unsigned int s0, s1, s2, b;

//----------------------------------------------
//
/*!
*/
//

unsigned int taus(void)
{

  b = (((s0 << 13) ^ s0) >> 19);
  s0 = (((s0 & 0xFFFFFFFE) << 12)^  b);
  b = (((s1 << 2) ^ s1) >> 25);
  s1 = (((s1 & 0xFFFFFFF8) << 4)^  b);
  b = (((s2 << 3) ^ s2) >> 11);
  s2 = (((s2 & 0xFFFFFFF0) << 17)^  b);
  return s0 ^ s1 ^ s2;
}

void set_taus_seed(unsigned int seed_init)
{

#ifdef USER_MODE
  struct drand48_data buffer;
  unsigned long result = 0;
#endif

  if (seed_init == 0) {
    s0 = (unsigned int)time(NULL);
    s1 = (unsigned int)time(NULL);
    s2 = (unsigned int)time(NULL);
  } else {
#ifndef USER_MODE
    s0 = (unsigned int)0x1e23d852;
    s1 = (unsigned int)0x81f38a1c;
    s2 = (unsigned int)0xfe1a133e;
#else
    /* Use reentrant version of rand48 to ensure that no conflicts with other generators occur */
    srand48_r((long int)seed_init, &buffer);
    mrand48_r(&buffer, (long int *)&result);
    s0 = result;
    mrand48_r(&buffer, (long int *)&result);
    s1 = result;
    mrand48_r(&buffer, (long int *)&result);
    s2 = result;
#endif
  }
}

#ifdef MAIN

main()
{

  unsigned int i,rand;

  set_taus_seed();

  for (i=0; i<10; i++) {

    rand = taus();
    printf("%u\n",rand);

  }
}
#endif //MAIN