int
mpz_si_kronecker (long a, mpz_srcptr b)
{
mp_srcptr b_ptr;
mp_limb_t b_low;
mp_size_t b_size;
mp_size_t b_abs_size;
mp_limb_t a_limb, b_rem;
unsigned twos;
int result_bit1;
#if GMP_NUMB_BITS < BITS_PER_ULONG
if (a > GMP_NUMB_MAX || a < -GMP_NUMB_MAX)
{
mp_limb_t alimbs[2];
mpz_t az;
ALLOC(az) = numberof (alimbs);
PTR(az) = alimbs;
mpz_set_si (az, a);
return mpz_kronecker (az, b);
}
#endif
b_size = SIZ (b);
if (b_size == 0)
return JACOBI_S0 (a); /* (a/0) */
/* account for the effect of the sign of b, then ignore it */
result_bit1 = JACOBI_BSGN_SS_BIT1 (a, b_size);
b_ptr = PTR(b);
b_low = b_ptr[0];
b_abs_size = ABS (b_size);
if ((b_low & 1) != 0)
{
/* b odd */
result_bit1 ^= JACOBI_ASGN_SU_BIT1 (a, b_low);
a_limb = (unsigned long) ABS(a);
if ((a_limb & 1) == 0)
{
/* (0/b)=1 for b=+/-1, 0 otherwise */
if (a_limb == 0)
return (b_abs_size == 1 && b_low == 1);
/* a even, b odd */
count_trailing_zeros (twos, a_limb);
a_limb >>= twos;
/* (a*2^n/b) = (a/b) * twos(n,a) */
result_bit1 ^= JACOBI_TWOS_U_BIT1 (twos, b_low);
}
}
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 = (unsigned long) ABS (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);
}
