BN_mod_sub_quick
if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, group->field))
if (!BN_mod_sub_quick(rh, rh, tmp, p))
|| !BN_mod_sub_quick(t4, t3, group->a, group->field)
|| !BN_mod_sub_quick(r->X, t4, t5, group->field)
|| !BN_mod_sub_quick(t3, t4, t3, group->field)
|| !BN_mod_sub_quick(s->X, t0, t4, group->field)
|| !BN_mod_sub_quick(t1, t1, t4, group->field)
|| !BN_mod_sub_quick(t1, t1, t5, group->field)
|| !BN_mod_sub_quick(t3, t4, t6, group->field)
|| !BN_mod_sub_quick(r->X, t3, t0, group->field)
|| !BN_mod_sub_quick(t0, t0, r->X, group->field)
|| !BN_mod_sub_quick(t0, t6, t0, group->field)
if (!BN_mod_sub_quick(n5, n1, n3, p))
if (!BN_mod_sub_quick(n6, n2, n4, p))
if (!BN_mod_sub_quick(r->X, n0, n3, p))
if (!BN_mod_sub_quick(n0, n3, n0, p))
if (!BN_mod_sub_quick(n0, n0, n1, p))
if (!BN_mod_sub_quick(n2, a->X, n1, p))
if (!BN_mod_sub_quick(r->X, r->X, n0, p))
if (!BN_mod_sub_quick(n0, n2, r->X, p))
if (!BN_mod_sub_quick(r->Y, n0, n3, p))
int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,