Error, error, unsupported BITS_PER_MP_LIMB
#endif
int
mpz_kronecker_ui (mpz_srcptr a, unsigned long b)
{
mp_srcptr a_ptr = PTR(a);
mp_size_t a_size;
mp_limb_t a_rem;
int result_bit1;
a_size = SIZ(a);
if (a_size == 0)
return JACOBI_0U (b);
if (b > GMP_NUMB_MAX)
{
mp_limb_t blimbs[2];
mpz_t bz;
ALLOC(bz) = numberof (blimbs);
PTR(bz) = blimbs;
mpz_set_ui (bz, b);
return mpz_kronecker (a, bz);
}
if ((b & 1) != 0)
{
result_bit1 = JACOBI_ASGN_SU_BIT1 (a_size, b);
}
else
{
mp_limb_t a_low = a_ptr[0];
int twos;
if (b == 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);
b >>= twos;
result_bit1 = (JACOBI_TWOS_U_BIT1 (twos, a_low)
^ JACOBI_ASGN_SU_BIT1 (a_size, b));
}
if (b == 1)
return JACOBI_BIT1_TO_PN (result_bit1); /* (a/1)=1 for any a */
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);
return mpn_jacobi_base (a_rem, (mp_limb_t) b, result_bit1);
}
int
mpn_jacobi_base (mp_limb_t a, mp_limb_t b, int result_bit1)
{
ASSERT (b & 1); /* b odd */
ASSERT (b != 1);
ASSERT (a <= b);
if (a == 0)
return 0;
PROCESS_TWOS_ANY;
if (a == 1)
goto done;
for (;;)
{
result_bit1 ^= JACOBI_RECIP_UU_BIT1 (a, b);
MP_LIMB_T_SWAP (a, b);
do
{
/* working on (a/b), a,b odd, a>=b */
ASSERT (a & 1);
ASSERT (b & 1);
ASSERT (a >= b);
if ((a -= b) == 0)
return 0;
PROCESS_TWOS_EVEN;
if (a == 1)
goto done;
}
while (a >= b);
}
done:
return JACOBI_BIT1_TO_PN (result_bit1);
}
int
mpz_ui_kronecker (unsigned long a, mpz_srcptr b)
{
mp_srcptr b_ptr;
mp_limb_t b_low;
int b_abs_size;
mp_limb_t b_rem;
int twos;
int result_bit1;
/* (a/-1)=1 when a>=0, so the sign of b is ignored */
b_abs_size = ABSIZ (b);
if (b_abs_size == 0)
return JACOBI_U0 (a); /* (a/0) */
if (a > GMP_NUMB_MAX)
{
mp_limb_t alimbs[2];
mpz_t az;
ALLOC(az) = numberof (alimbs);
PTR(az) = alimbs;
mpz_set_ui (az, a);
return mpz_kronecker (az, b);
}
b_ptr = PTR(b);
b_low = b_ptr[0];
result_bit1 = 0;
if (! (b_low & 1))
{
/* (0/b)=0 for b!=+/-1; and (even/even)=0 */
if (! (a & 1))
return 0;
/* a odd, b even
Establish shifted b_low with valid bit1 for the RECIP below. Zero
limbs stripped are accounted for, but zero bits on b_low are not
because they remain in {b_ptr,b_abs_size} for
JACOBI_MOD_OR_MODEXACT_1_ODD. */
JACOBI_STRIP_LOW_ZEROS (result_bit1, a, b_ptr, b_abs_size, b_low);
if (! (b_low & 1))
{
if (UNLIKELY (b_low == GMP_NUMB_HIGHBIT))
{
/* need b_ptr[1] to get bit1 in b_low */
if (b_abs_size == 1)
{
/* (a/0x80...00) == (a/2)^(NUMB-1) */
if ((GMP_NUMB_BITS % 2) == 0)
{
/* JACOBI_STRIP_LOW_ZEROS does nothing to result_bit1
when GMP_NUMB_BITS is even, so it's still 0. */
ASSERT (result_bit1 == 0);
result_bit1 = JACOBI_TWO_U_BIT1 (a);
}
return JACOBI_BIT1_TO_PN (result_bit1);
}
/* b_abs_size > 1 */
b_low = b_ptr[1] << 1;
}
else
{
count_trailing_zeros (twos, b_low);
b_low >>= twos;
}
}
}
else
{
if (a == 0) /* (0/b)=1 for b=+/-1, 0 otherwise */
