int
main(void)
{
int i, result;
flint_rand_t state;
printf("fmpz....");
fflush(stdout);
for (i = 0; i < 100000; i++)
{
fmpz_t a, b;
*a = 0L;
fmpz_randtest(a, state, FLINT_BITS - 2);
*b = *a;
_fmpz_promote_val(a);
_fmpz_demote_val(a);
result = (*b == *a);
if (!result)
{
printf("FAIL\n");
abort();
}
}
_fmpz_cleanup();
printf("PASS\n");
return 0;
}
void
fmpz_addmul_ui(fmpz_t f, const fmpz_t g, ulong x)
{
fmpz c1, r;
c1 = *g;
if ((x == 0) || (c1 == 0)) /* product is zero */
return;
r = *f;
if (r == 0)
{
fmpz_mul_ui(f, g, x); /* we are adding product to 0 */
return;
}
if (x == UWORD(1)) /* special case, adding g*1 to f */
{
fmpz_add(f, f, g);
return;
}
if (c1 == UWORD(1)) /* special case, adding 1*x to f */
{
fmpz_add_ui(f, f, x);
return;
}
if (!COEFF_IS_MPZ(c1)) /* c1 is small */
{
mp_limb_t prod[2];
ulong uc1 = FLINT_ABS(c1);
umul_ppmm(prod[1], prod[0], uc1, x); /* compute product */
if (prod[1] == 0) /* product fits in one limb */
{
if (c1 < WORD(0))
fmpz_sub_ui(f, f, prod[0]);
else
fmpz_add_ui(f, f, prod[0]);
return;
}
else if ((prod[1] == 1) && (!COEFF_IS_MPZ(r)) && ((r ^ c1) < WORD(0)))
{
/*
only chance at cancellation is if product is one bit past
a limb and res is small and opposite sign to this product
*/
ulong ur = FLINT_ABS(r);
if (ur > prod[0]) /* cancellation will occur */
{
fmpz_set_ui(f, prod[0] - ur);
if (r > WORD(0))
fmpz_neg(f, f);
return;
}
}
/*
in all remaining cases res is either big already,
or will be big in the end
*/
{
__mpz_struct * mpz_ptr = _fmpz_promote_val(f);
mpz_t temp; /* set up a temporary, cheap mpz_t to contain prod */
temp->_mp_d = prod;
temp->_mp_size = (c1 < WORD(0) ? -2 : 2);
mpz_add(mpz_ptr, mpz_ptr, temp);
_fmpz_demote_val(f); /* cancellation may have occurred */
}
}
else /* c1 is large */
{
__mpz_struct * mpz_ptr = _fmpz_promote_val(f);
flint_mpz_addmul_ui(mpz_ptr, COEFF_TO_PTR(c1), x);
_fmpz_demote_val(f); /* cancellation may have occurred */
}
}
