GF2X_STORAGE_CLASS_mul2 void gf2x_mul2(unsigned long *c, const unsigned long *a, const unsigned long *b)
{
unsigned long t;
unsigned long u[2];
gf2x_mul1 (c, a[0], b[0]);
gf2x_mul1 (c+2, a[1], b[1]);
t = c[1]^c[2];
gf2x_mul1 (u, a[0]^a[1], b[0]^b[1]);
c[1] = c[0]^u[0]^t;
c[2] = c[3]^u[1]^t;
}
/* uses the variant of Karatsuba with 6 multiplications */
GF2X_STORAGE_CLASS_mul3
void gf2x_mul3 (unsigned long *c, const unsigned long *a, const unsigned long *b)
{
unsigned long aa[3], bb[3];
unsigned long p0[2], p1[2], p2[2];
unsigned long pp0[2], pp1[2], pp2[2];
aa[0] = a[1]^a[2];
aa[1] = a[0]^a[2];
aa[2] = a[0]^a[1];
bb[0] = b[1]^b[2];
bb[1] = b[0]^b[2];
bb[2] = b[0]^b[1];
gf2x_mul1 (p0, a[0], b[0]);
gf2x_mul1 (p1, a[1], b[1]);
gf2x_mul1 (p2, a[2], b[2]);
gf2x_mul1 (pp0, aa[0], bb[0]);
gf2x_mul1 (pp1, aa[1], bb[1]);
gf2x_mul1 (pp2, aa[2], bb[2]);
c[0] = p0[0];
c[1] = p0[0]^p1[0]^pp2[0] ^ p0[1];
c[2] = p0[0]^p1[0]^p2[0]^pp1[0] ^ p0[1]^p1[1]^pp2[1];
c[3] = pp0[0]^p1[0]^p2[0] ^ p0[1]^p1[1]^p2[1]^pp1[1];
c[4] = p2[0] ^ pp0[1]^p1[1]^p2[1];
c[5] = p2[1];
}
