OpenXM_contrib/gmp/mpz/kronzu.c - diff

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Diff for /OpenXM_contrib/gmp/mpz/Attic/kronzu.c between version 1.1.1.1 and 1.1.1.2

-version 1.1.1.1, 2000/09/09 14:12:54
+version 1.1.1.2, 2003/08/25 16:06:33
 Line 1
 Line 1
 Line 1
- /* mpz_kronecker_ui -- Kronecker/Jacobi symbol. */
+ /* mpz_kronecker_ui -- mpz+ulong Kronecker/Jacobi symbol.
- /*
+ Copyright 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
- Copyright (C) 1999, 2000 Free Software Foundation, Inc.
  This file is part of the GNU MP Library.
-Line 18  License for more details.
+Line 17  License for more details.
 Line 18  License for more details.
 Line 17  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.
+ MA 02111-1307, USA. */
- */
  #include "gmp.h"
  #include "gmp-impl.h"
  #include "longlong.h"
- /* This function is expected to be often used with b an odd prime, so the
+ /* This implementation depends on BITS_PER_MP_LIMB being even, so that
-    code for odd b is nice and short. */
+    (a/2)^BITS_PER_MP_LIMB = 1 and so there's no need to pay attention to how
+    many low zero limbs are stripped.  */
+ #if BITS_PER_MP_LIMB % 2 != 0
+ Error, error, unsupported BITS_PER_MP_LIMB
+ #endif
  int
- #if __STDC__
  mpz_kronecker_ui (mpz_srcptr a, unsigned long b)
- #else
- mpz_kronecker_ui (a, b)
-      mpz_srcptr    a;
-      unsigned long b;
- #endif
  {
-   int  twos;
+   mp_srcptr  a_ptr = PTR(a);
+   mp_size_t  a_size;
+   mp_limb_t  a_rem;
+   int        result_bit1;
-   if (b & 1)
+   a_size = SIZ(a);
+   if (a_size == 0)
+     return JACOBI_0U (b);
+   if (b > GMP_NUMB_MAX)
      {
-       if (b != 1)
+       mp_limb_t  blimbs[2];
-         return mpn_jacobi_base (mpz_fdiv_ui (a, b), b, 0);
+       mpz_t      bz;
-       else
+       ALLOC(bz) = numberof (blimbs);
-         return 1;  /* (a/1)=1 for any a */
+       PTR(bz) = blimbs;
+       mpz_set_ui (bz, b);
+       return mpz_kronecker (a, bz);
      }
-   if (b == 0)
+   if ((b & 1) != 0)
-     return JACOBI_Z0 (a);
+     {
+       result_bit1 = JACOBI_ASGN_SU_BIT1 (a_size, b);
+     }
+   else
+     {
+       mp_limb_t  a_low = a_ptr[0];
+       int        twos;
-   /* (a/2)=0 if a even */
+       if (b == 0)
-   if (mpz_even_p (a))
+         return JACOBI_LS0 (a_low, a_size);   /* (a/0) */
-     return 0;
-   /* (a/2)=(2/a) when a odd */
+       if (! (a_low & 1))
-   count_trailing_zeros (twos, b);
+         return 0;  /* (even/even)=0 */
-   b >>= twos;
+       /* (a/2)=(2/a) for a odd */
+       count_trailing_zeros (twos, b);
+       b >>= twos;
+       result_bit1 = (JACOBI_TWOS_U_BIT1 (twos, a_low)
+                      ^ JACOBI_ASGN_SU_BIT1 (a_size, b));
+     }
    if (b == 1)
-     return JACOBI_TWOS_U (twos, PTR(a)[0]);
+     return JACOBI_BIT1_TO_PN (result_bit1);  /* (a/1)=1 for any a */
-   return mpn_jacobi_base (mpz_fdiv_ui (a, b), b,
+   a_size = ABS(a_size);
-                           JACOBI_TWOS_U_BIT1(twos, PTR(a)[0]));
+   /* (a/b) = (a mod b / b) */
+   JACOBI_MOD_OR_MODEXACT_1_ODD (result_bit1, a_rem, a_ptr, a_size, b);
+   return mpn_jacobi_base (a_rem, (mp_limb_t) b, result_bit1);
  }

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