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-rw-r--r--rts/gmp/mpz/kronuz.c115
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diff --git a/rts/gmp/mpz/kronuz.c b/rts/gmp/mpz/kronuz.c
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+/* mpz_ui_kronecker -- Kronecker/Jacobi symbol. */
+
+/*
+Copyright (C) 1999, 2000 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 the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or (at your
+option) any later version.
+
+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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library; see the file COPYING.LIB. If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA.
+*/
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+
+
+int
+#if __STDC__
+mpz_ui_kronecker (unsigned long a, mpz_srcptr b)
+#else
+mpz_ui_kronecker (a, b)
+ unsigned long a;
+ mpz_srcptr b;
+#endif
+{
+ int b_abs_size;
+ mp_srcptr b_ptr;
+ mp_limb_t b_low;
+ int twos;
+ int result_bit1;
+
+ /* (a/0) */
+ b_abs_size = ABSIZ (b);
+ if (b_abs_size == 0)
+ return JACOBI_U0 (a);
+
+ /* (a/-1)=1 when a>=0, so the sign of b is ignored */
+ b_ptr = PTR(b);
+ b_low = b_ptr[0];
+
+ /* (0/1)=1; (0/-1)=1; (0/b)=0 for b!=+/-1
+ (1/b)=1, for any b */
+ if (a <= 1)
+ return (a == 1) | ((b_abs_size == 1) & (b_low == 1));
+
+ if (b_low & 1)
+ {
+ /* (a/1) = 1 for any a */
+ if (b_abs_size == 1 && b_low == 1)
+ return 1;
+
+ count_trailing_zeros (twos, a);
+ a >>= twos;
+ if (a == 1)
+ return JACOBI_TWOS_U (twos, b_low); /* powers of (2/b) only */
+
+ /* powers of (2/b); reciprocity to (b/a); (b/a) == (b mod a / a) */
+ return mpn_jacobi_base (mpn_mod_1 (b_ptr, b_abs_size, a),
+ a,
+ JACOBI_TWOS_U_BIT1 (twos, b_low)
+ ^ JACOBI_RECIP_UU_BIT1 (b_low, a));
+ }
+
+ /* b is even; (a/2)=0 if a is even */
+ if ((a & 1) == 0)
+ return 0;
+
+ /* Require MP_BITS_PER_LIMB even, so (a/2)^MP_BITS_PER_LIMB = 1, and so we
+ don't have to pay attention to how many trailing zero limbs are
+ stripped. */
+ ASSERT ((BITS_PER_MP_LIMB & 1) == 0);
+
+ MPN_STRIP_LOW_ZEROS_NOT_ZERO (b_ptr, b_abs_size);
+ b_low = b_ptr[0];
+
+ if (b_low & 1)
+ /* reciprocity to (b/a); (b/a) == (b mod a / a) */
+ return mpn_jacobi_base (mpn_mod_1 (b_ptr, b_abs_size, a),
+ a,
+ JACOBI_RECIP_UU_BIT1 (b_low, a));
+
+ count_trailing_zeros (twos, b_low);
+
+ /* reciprocity to get (b/a) */
+ if (twos == BITS_PER_MP_LIMB-1)
+ {
+ if (b_abs_size == 1)
+ {
+ /* b==0x800...00, one limb high bit only, so (a/2)^(BPML-1) */
+ return JACOBI_TWOS_U (BITS_PER_MP_LIMB-1, a);
+ }
+
+ /* b_abs_size > 1 */
+ result_bit1 = JACOBI_RECIP_UU_BIT1 (a, b_ptr[1] << 1);
+ }
+ else
+ result_bit1 = JACOBI_RECIP_UU_BIT1 (a, b_low >> twos);
+
+ /* powers of (a/2); reciprocity to (b/a); (b/a) == (b mod a / a) */
+ return mpn_jacobi_base (mpn_mod_1_rshift (b_ptr, b_abs_size, twos, a),
+ a,
+ JACOBI_TWOS_U_BIT1 (twos, a) ^ result_bit1);
+}