int test_divv(testspec_t *t, FILE *ofp)
{
mp_int in[3], out[2];
mp_result res, expect;
int v, rem, orem;
if(!parse_int_values(t, in, out, &expect))
return imath_errno = MP_BADARG, 0;
if((res = mp_int_to_int(in[1], &v)) != MP_OK)
return imath_errno = res, 0;
if((res = mp_int_to_int(out[1], &orem)) != MP_OK)
return imath_errno = res, 0;
if((res = mp_int_div_value(in[0], v, in[2], &rem)) != expect)
return imath_errno = res, 0;
if(expect == MP_OK &&
((mp_int_compare(in[2], out[0]) != 0) || (rem != orem))) {
char *str;
mp_int_to_string(in[2], 10, g_output, OUTPUT_LIMIT);
str = g_output + strlen(g_output);
*str++ = ',';
sprintf(str, "%d", rem);
return imath_errno = OTHER_ERROR, 0;
}
return 1;
}
/*
Compute mul * atan(1/x) to prec digits of precision, and store the
result in sum.
Computes atan(1/x) using the formula:
1 1 1 1
atan(1/x) = --- - ---- + ---- - ---- + ...
x 3x^3 5x^5 7x^7
*/
mp_result arctan(mp_small radix, mp_small mul, mp_small x, mp_small prec,
mp_int sum) {
mpz_t t, v;
mp_result res;
mp_small rem, sign = 1, coeff = 1;
mp_int_init(&t);
mp_int_init(&v);
++prec;
/* Compute mul * radix^prec * x
The initial multiplication by x saves a special case in the loop for
the first term of the series.
*/
if ((res = mp_int_expt_value(radix, prec, &t)) != MP_OK ||
(res = mp_int_mul_value(&t, mul, &t)) != MP_OK ||
(res = mp_int_mul_value(&t, x, &t)) != MP_OK)
goto CLEANUP;
x *= x; /* assumes x <= sqrt(MP_SMALL_MAX) */
mp_int_zero(sum);
do {
if ((res = mp_int_div_value(&t, x, &t, &rem)) != MP_OK) goto CLEANUP;
if ((res = mp_int_div_value(&t, coeff, &v, &rem)) != MP_OK) goto CLEANUP;
/* Add or subtract the result depending on the current sign (1 = add) */
if (sign > 0)
res = mp_int_add(sum, &v, sum);
else
res = mp_int_sub(sum, &v, sum);
if (res != MP_OK) goto CLEANUP;
sign = -sign;
coeff += 2;
} while (mp_int_compare_zero(&t) != 0);
res = mp_int_div_value(sum, radix, sum, NULL);
CLEANUP:
mp_int_clear(&v);
mp_int_clear(&t);
return res;
}
/* Test whether z is likely to be prime:
MP_TRUE means it is probably prime
MP_FALSE means it is definitely composite
*/
mp_result mp_int_is_prime(mp_int z)
{
int i, rem;
mp_result res;
/* First check for divisibility by small primes; this eliminates a
large number of composite candidates quickly
*/
for(i = 0; i < s_ptab_size; ++i) {
if((res = mp_int_div_value(z, s_ptab[i], NULL, &rem)) != MP_OK)
return res;
if(rem == 0)
return MP_FALSE;
}
/* Now try Fermat's test for several prime witnesses (since we now
know from the above that z is not a multiple of any of them)
*/
{
mpz_t tmp;
if((res = mp_int_init(&tmp)) != MP_OK) return res;
for(i = 0; i < 10 && i < s_ptab_size; ++i) {
if((res = mp_int_exptmod_bvalue(s_ptab[i], z, z, &tmp)) != MP_OK)
return res;
if(mp_int_compare_value(&tmp, s_ptab[i]) != 0) {
mp_int_clear(&tmp);
return MP_FALSE;
}
}
mp_int_clear(&tmp);
}
return MP_TRUE;
}
