int
mprime(unsigned int *n)
{
int i, k;
unsigned int *q;
// 1?
if (MLENGTH(n) == 1 && n[0] == 1)
return 0;
// 2?
if (MLENGTH(n) == 1 && n[0] == 2)
return 1;
// even?
if ((n[0] & 1) == 0)
return 0;
// n = 1 + (2 ^ k) q
q = mcopy(n);
k = 0;
do {
mshiftright(q);
k++;
} while ((q[0] & 1) == 0);
// try 25 times
for (i = 0; i < 25; i++)
if (mprimef(n, q, k) == 0)
break;
mfree(q);
if (i < 25)
return 0;
else
return 1;
}
unsigned int *
mgcd(unsigned int *u, unsigned int *v)
{
int i, k, n;
unsigned int *t;
if (MZERO(u)) {
t = mcopy(v);
MSIGN(t) = 1;
return t;
}
if (MZERO(v)) {
t = mcopy(u);
MSIGN(t) = 1;
return t;
}
u = mcopy(u);
v = mcopy(v);
MSIGN(u) = 1;
MSIGN(v) = 1;
k = 0;
while ((u[0] & 1) == 0 && (v[0] & 1) == 0) {
mshiftright(u);
mshiftright(v);
k++;
}
if (u[0] & 1) {
t = mcopy(v);
MSIGN(t) *= -1;
} else
t = mcopy(u);
while (1) {
while ((t[0] & 1) == 0)
mshiftright(t);
if (MSIGN(t) == 1) {
mfree(u);
u = mcopy(t);
} else {
mfree(v);
v = mcopy(t);
MSIGN(v) *= -1;
}
mfree(t);
t = msub(u, v);
if (MZERO(t)) {
mfree(t);
mfree(v);
n = (k / 32) + 1;
v = mnew(n);
MSIGN(v) = 1;
MLENGTH(v) = n;
for (i = 0; i < n; i++)
v[i] = 0;
mp_set_bit(v, k);
t = mmul(u, v);
mfree(u);
mfree(v);
return t;
}
}
}
