accum = big.NewInt(0)
	denom = big.NewInt(1)
	ten   = big.NewInt(10)
)

func extractDigit() int64 {
	if big.CmpInt(numer, accum) > 0 {
		return -1
	}
	tmp1.Lsh(numer, 1).Add(tmp1, numer).Add(tmp1, accum)
	big.DivModInt(tmp1, tmp2, tmp1, denom)
	tmp2.Add(tmp2, numer)
	if big.CmpInt(tmp2, denom) >= 0 {
		return -1
	}
	return tmp1.Int64()
}

func nextTerm(k int64) {
	y2 := k*2 + 1

	x.doinit()
	z.doinit()
	C.mpz_abs(&z.i[0], &x.i[0])
	return z
}

/*
 * functions without a clear receiver
 */

// CmpInt compares x and y. The result is
//
//	-1 if x <  y
//	 0 if x == y
//	+1 if x >  y
func CmpInt(x, y *Int) int {
	x.doinit()
	y.doinit()
	switch cmp := C.mpz_cmp(&x.i[0], &y.i[0]); {
	case cmp < 0:
		return -1
	case cmp == 0:
		return 0
	}