1 | /* gmp_randinit_lc_2exp (state, a, c, m2exp) -- Initialize random |
---|

2 | state STATE for a linear congruential generator with multiplier A, |
---|

3 | adder C, and modulus 2 ^ M2EXP. |
---|

4 | |
---|

5 | Copyright 2000, 2002, 2004 Free Software Foundation, Inc. |
---|

6 | |
---|

7 | This file is part of the GNU MP Library. |
---|

8 | |
---|

9 | The GNU MP Library is free software; you can redistribute it and/or modify |
---|

10 | it under the terms of the GNU Lesser General Public License as published by |
---|

11 | the Free Software Foundation; either version 2.1 of the License, or (at your |
---|

12 | option) any later version. |
---|

13 | |
---|

14 | The GNU MP Library is distributed in the hope that it will be useful, but |
---|

15 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
---|

16 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
---|

17 | License for more details. |
---|

18 | |
---|

19 | You should have received a copy of the GNU Lesser General Public License |
---|

20 | along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
---|

21 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
---|

22 | MA 02111-1307, USA. */ |
---|

23 | |
---|

24 | #include "gmp.h" |
---|

25 | #include "gmp-impl.h" |
---|

26 | |
---|

27 | void |
---|

28 | gmp_randinit_lc_2exp (gmp_randstate_t rstate, |
---|

29 | mpz_srcptr a, |
---|

30 | unsigned long int c, |
---|

31 | unsigned long int m2exp) |
---|

32 | { |
---|

33 | mpz_init_set_ui (rstate->_mp_seed, 1); |
---|

34 | _mpz_realloc (rstate->_mp_seed, (m2exp + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS); |
---|

35 | |
---|

36 | /* Allocate algorithm specific data. */ |
---|

37 | rstate->_mp_algdata._mp_lc = (__gmp_randata_lc *) |
---|

38 | (*__gmp_allocate_func) (sizeof (__gmp_randata_lc)); |
---|

39 | |
---|

40 | mpz_init (rstate->_mp_algdata._mp_lc->_mp_a); |
---|

41 | mpz_fdiv_r_2exp (rstate->_mp_algdata._mp_lc->_mp_a, a, m2exp); |
---|

42 | |
---|

43 | if (m2exp < BITS_PER_ULONG) |
---|

44 | c &= ((1L << m2exp) - 1); |
---|

45 | rstate->_mp_algdata._mp_lc->_mp_c = c; |
---|

46 | |
---|

47 | /* Cover weird case where m2exp is 0, which means that m is used |
---|

48 | instead of m2exp. */ |
---|

49 | if (m2exp == 0) |
---|

50 | mpz_init_set_ui (rstate->_mp_algdata._mp_lc->_mp_m, 0); |
---|

51 | rstate->_mp_algdata._mp_lc->_mp_m2exp = m2exp; |
---|

52 | |
---|

53 | rstate->_mp_alg = GMP_RAND_ALG_LC; |
---|

54 | } |
---|