top(1): Raise WARNS to 6 and fix warnings.
[dragonfly.git] / contrib / gmp / mpz / kronzu.c
blobe73a0f86ae9971ee89f25a6fd7a85d8908bf241b
1 /* mpz_kronecker_ui -- mpz+ulong Kronecker/Jacobi symbol.
3 Copyright 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of the GNU MP Library.
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or (at your
10 option) any later version.
12 The GNU MP Library is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15 License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
20 #include "gmp.h"
21 #include "gmp-impl.h"
22 #include "longlong.h"
25 int
26 mpz_kronecker_ui (mpz_srcptr a, unsigned long b)
28 mp_srcptr a_ptr;
29 mp_size_t a_size;
30 mp_limb_t a_rem;
31 int result_bit1;
33 a_size = SIZ(a);
34 if (a_size == 0)
35 return JACOBI_0U (b);
37 if (b > GMP_NUMB_MAX)
39 mp_limb_t blimbs[2];
40 mpz_t bz;
41 ALLOC(bz) = numberof (blimbs);
42 PTR(bz) = blimbs;
43 mpz_set_ui (bz, b);
44 return mpz_kronecker (a, bz);
47 a_ptr = PTR(a);
48 if ((b & 1) != 0)
50 result_bit1 = JACOBI_ASGN_SU_BIT1 (a_size, b);
52 else
54 mp_limb_t a_low = a_ptr[0];
55 int twos;
57 if (b == 0)
58 return JACOBI_LS0 (a_low, a_size); /* (a/0) */
60 if (! (a_low & 1))
61 return 0; /* (even/even)=0 */
63 /* (a/2)=(2/a) for a odd */
64 count_trailing_zeros (twos, b);
65 b >>= twos;
66 result_bit1 = (JACOBI_TWOS_U_BIT1 (twos, a_low)
67 ^ JACOBI_ASGN_SU_BIT1 (a_size, b));
70 if (b == 1)
71 return JACOBI_BIT1_TO_PN (result_bit1); /* (a/1)=1 for any a */
73 a_size = ABS(a_size);
75 /* (a/b) = (a mod b / b) */
76 JACOBI_MOD_OR_MODEXACT_1_ODD (result_bit1, a_rem, a_ptr, a_size, b);
77 return mpn_jacobi_base (a_rem, (mp_limb_t) b, result_bit1);