// (public) this^e % m, 0 <= e < 2^32
public BigInteger modPowInt(int e, BigInteger m)
{
BigInteger r = new BigInteger();
if (e < 256 || m.isEven())
{
Classic z = new Classic(m);
r = this.exp(e, z);
}
else
{
Montgomery z = new Montgomery(m);
r = this.exp(e, z);
}
return r;
}
// (protected) this^e, e < 2^32, doing sqr and mul with "r" (HAC 14.79)
public BigInteger exp(int e, Classic z)
{
if (e > 0x7fffffff || e < 1)
{
return ONE;
}
BigInteger r = new BigInteger(), r2 = new BigInteger();
BigInteger g = z.convert(this);
int i = nbits(e) - 1;
g.copyTo(r);
while (--i >= 0)
{
z.sqrTo(r, r2);
if ((e & (1 << i)) > 0)
{
z.mulTo(r2, g, r);
}
else
{
BigInteger t = r;
r = r2;
r2 = t;
}
}
return z.revert(r);
}