bn_cmp_words
int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n);
return bn_cmp_words(a, b, cl);
c1 = bn_cmp_words(&(a[0]), &(a[n]), n);
c2 = bn_cmp_words(&(b[n]), &(b[0]), n);
c1 = bn_cmp_words(a, &(a[n]), n);