MP_DEST(d, MP_LEN(a) + MP_LEN(b), a->f | b->f | MP_UNDEF);
mpx_umul(d->v, d->vl, a->v, a->vl, b->v, b->vl);
} else {
size_t m = 2 * MAX(MP_LEN(a), MP_LEN(b)) + 2;
mpw *s;
MP_DEST(d, m, a->f | b->f | MP_UNDEF);
MP_DEST(d, MP_LEN(a) + MP_LEN(b), a->f | b->f | MP_UNDEF);
mpx_umul(d->v, d->vl, a->v, a->vl, b->v, b->vl);
} else {
size_t m = 2 * MAX(MP_LEN(a), MP_LEN(b)) + 2;
mpw *s;
MP_DEST(d, m, a->f | b->f | MP_UNDEF);
s = mpalloc(d->a, m);
mpx_kmul(d->v, d->vl, a->v, a->vl, b->v, b->vl, s, s + m);
mpfree(d->a, s);
s = mpalloc(d->a, m);
mpx_kmul(d->v, d->vl, a->v, a->vl, b->v, b->vl, s, s + m);
mpfree(d->a, s);
s = mpalloc(d->a, m);
mpx_ksqr(d->v, d->vl, a->v, a->vl, s, s + m);
mpfree(d->a, s);
s = mpalloc(d->a, m);
mpx_ksqr(d->v, d->vl, a->v, a->vl, s, s + m);
mpfree(d->a, s);