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-rw-r--r--gmp-6.3.0/mpz/kronzs.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/gmp-6.3.0/mpz/kronzs.c b/gmp-6.3.0/mpz/kronzs.c
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+++ b/gmp-6.3.0/mpz/kronzs.c
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+/* mpz_kronecker_si -- mpz+long Kronecker/Jacobi symbol.
+
+Copyright 1999-2002 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of either:
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your
+ option) any later version.
+
+or
+
+ * the GNU General Public License as published by the Free Software
+ Foundation; either version 2 of the License, or (at your option) any
+ later version.
+
+or both in parallel, as here.
+
+The GNU MP Library 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 copies of the GNU General Public License and the
+GNU Lesser General Public License along with the GNU MP Library. If not,
+see https://www.gnu.org/licenses/. */
+
+#include "gmp-impl.h"
+#include "longlong.h"
+
+
+/* After the absolute value of b is established it's treated as an unsigned
+ long, because 0x80..00 doesn't fit in a signed long. */
+
+int
+mpz_kronecker_si (mpz_srcptr a, long b)
+{
+ mp_srcptr a_ptr;
+ mp_size_t a_size;
+ mp_limb_t a_rem, b_limb;
+ int result_bit1;
+
+ a_size = SIZ(a);
+ if (a_size == 0)
+ return JACOBI_0S (b);
+
+#if GMP_NUMB_BITS < BITS_PER_ULONG
+ if (b > GMP_NUMB_MAX || b < -GMP_NUMB_MAX)
+ {
+ mp_limb_t blimbs[2];
+ mpz_t bz;
+ ALLOC(bz) = numberof (blimbs);
+ PTR(bz) = blimbs;
+ mpz_set_si (bz, b);
+ return mpz_kronecker (a, bz);
+ }
+#endif
+
+ result_bit1 = JACOBI_BSGN_SS_BIT1 (a_size, b);
+ b_limb = ABS_CAST (unsigned long, b);
+ a_ptr = PTR(a);
+
+ if ((b_limb & 1) == 0)
+ {
+ mp_limb_t a_low = a_ptr[0];
+ int twos;
+
+ if (b_limb == 0)
+ return JACOBI_LS0 (a_low, a_size); /* (a/0) */
+
+ if (! (a_low & 1))
+ return 0; /* (even/even)=0 */
+
+ /* (a/2)=(2/a) for a odd */
+ count_trailing_zeros (twos, b_limb);
+ b_limb >>= twos;
+ result_bit1 ^= JACOBI_TWOS_U_BIT1 (twos, a_low);
+ }
+
+ if (b_limb == 1)
+ return JACOBI_BIT1_TO_PN (result_bit1); /* (a/1)=1 for any a */
+
+ result_bit1 ^= JACOBI_ASGN_SU_BIT1 (a_size, b_limb);
+ a_size = ABS(a_size);
+
+ /* (a/b) = (a mod b / b) */
+ JACOBI_MOD_OR_MODEXACT_1_ODD (result_bit1, a_rem, a_ptr, a_size, b_limb);
+ return mpn_jacobi_base (a_rem, b_limb, result_bit1);
+}