static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['static int group_order_tests(EC_GROUP *group)\n{\n    BIGNUM *n1 = NULL, *n2 = NULL, *order = NULL;\n    EC_POINT *P = NULL, *Q = NULL, *R = NULL, *S = NULL;\n    const EC_POINT *G = NULL;\n    BN_CTX *ctx = NULL;\n    int i = 0, r = 0;\n    if (!TEST_ptr(n1 = BN_new())\n        || !TEST_ptr(n2 = BN_new())\n        || !TEST_ptr(order = BN_new())\n        || !TEST_ptr(ctx = BN_CTX_new())\n        || !TEST_ptr(G = EC_GROUP_get0_generator(group))\n        || !TEST_ptr(P = EC_POINT_new(group))\n        || !TEST_ptr(Q = EC_POINT_new(group))\n        || !TEST_ptr(R = EC_POINT_new(group))\n        || !TEST_ptr(S = EC_POINT_new(group)))\n        goto err;\n    if (!TEST_true(EC_GROUP_get_order(group, order, ctx))\n        || !TEST_true(EC_POINT_mul(group, Q, order, NULL, NULL, ctx))\n        || !TEST_true(EC_POINT_is_at_infinity(group, Q))\n        || !TEST_true(EC_GROUP_precompute_mult(group, ctx))\n        || !TEST_true(EC_POINT_mul(group, Q, order, NULL, NULL, ctx))\n        || !TEST_true(EC_POINT_is_at_infinity(group, Q))\n        || !TEST_true(EC_POINT_copy(P, G))\n        || !TEST_true(BN_one(n1))\n        || !TEST_true(EC_POINT_mul(group, Q, n1, NULL, NULL, ctx))\n        || !TEST_int_eq(0, EC_POINT_cmp(group, Q, P, ctx))\n        || !TEST_true(BN_sub(n1, order, n1))\n        || !TEST_true(EC_POINT_mul(group, Q, n1, NULL, NULL, ctx))\n        || !TEST_true(EC_POINT_invert(group, Q, ctx))\n        || !TEST_int_eq(0, EC_POINT_cmp(group, Q, P, ctx)))\n        goto err;\n    for (i = 1; i <= 2; i++) {\n        const BIGNUM *scalars[6];\n        const EC_POINT *points[6];\n        if (!TEST_true(BN_set_word(n1, i))\n            || !TEST_true(EC_POINT_mul(group, P, n1, NULL, NULL, ctx))\n            || (i == 1 && !TEST_int_eq(0, EC_POINT_cmp(group, P, G, ctx)))\n            || !TEST_true(BN_one(n1))\n            || !TEST_true(BN_sub(n1, n1, order))\n            || !TEST_true(EC_POINT_mul(group, Q, NULL, P, n1, ctx))\n            || !TEST_int_eq(0, EC_POINT_cmp(group, Q, P, ctx))\n            || !TEST_true(BN_add(n2, order, BN_value_one()))\n            || !TEST_true(EC_POINT_mul(group, Q, NULL, P, n2, ctx))\n            || !TEST_int_eq(0, EC_POINT_cmp(group, Q, P, ctx))\n            || !TEST_true(BN_mul(n2, n1, n2, ctx))\n            || !TEST_true(EC_POINT_mul(group, Q, NULL, P, n2, ctx))\n            || !TEST_int_eq(0, EC_POINT_cmp(group, Q, P, ctx)))\n            goto err;\n        BN_set_negative(n2, 0);\n        if (!TEST_true(EC_POINT_mul(group, Q, NULL, P, n2, ctx))\n            || !TEST_true(EC_POINT_add(group, Q, Q, P, ctx))\n            || !TEST_true(EC_POINT_is_at_infinity(group, Q))\n            || !TEST_false(EC_POINT_is_at_infinity(group, P)))\n            goto err;\n        scalars[0] = scalars[1] = BN_value_one();\n        points[0]  = points[1]  = P;\n        if (!TEST_true(EC_POINTs_mul(group, R, NULL, 2, points, scalars, ctx))\n            || !TEST_true(EC_POINT_dbl(group, S, points[0], ctx))\n            || !TEST_int_eq(0, EC_POINT_cmp(group, R, S, ctx)))\n            goto err;\n        scalars[0] = n1;\n        points[0] = Q;\n        scalars[1] = n2;\n        points[1] = P;\n        scalars[2] = n1;\n        points[2] = Q;\n        scalars[3] = n2;\n        points[3] = Q;\n        scalars[4] = n1;\n        points[4] = P;\n        scalars[5] = n2;\n        points[5] = Q;\n        if (!TEST_true(EC_POINTs_mul(group, P, NULL, 6, points, scalars, ctx))\n            || !TEST_true(EC_POINT_is_at_infinity(group, P)))\n            goto err;\n    }\n    r = 1;\nerr:\n    if (r == 0 && i != 0)\n        TEST_info(i == 1 ? "allowing precomputation" :\n                           "without precomputation");\n    EC_POINT_free(P);\n    EC_POINT_free(Q);\n    EC_POINT_free(R);\n    EC_POINT_free(S);\n    BN_free(n1);\n    BN_free(n2);\n    BN_free(order);\n    BN_CTX_free(ctx);\n    return r;\n}', 'int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,\n                  size_t num, const EC_POINT *points[],\n                  const BIGNUM *scalars[], BN_CTX *ctx)\n{\n    int ret = 0;\n    size_t i = 0;\n    BN_CTX *new_ctx = NULL;\n    if ((scalar == NULL) && (num == 0)) {\n        return EC_POINT_set_to_infinity(group, r);\n    }\n    if (!ec_point_is_compat(r, group)) {\n        ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);\n        return 0;\n    }\n    for (i = 0; i < num; i++) {\n        if (!ec_point_is_compat(points[i], group)) {\n            ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);\n            return 0;\n        }\n    }\n    if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL) {\n        ECerr(EC_F_EC_POINTS_MUL, ERR_R_INTERNAL_ERROR);\n        return 0;\n    }\n    if (group->meth->mul != NULL)\n        ret = group->meth->mul(group, r, scalar, num, points, scalars, ctx);\n    else\n        ret = ec_wNAF_mul(group, r, scalar, num, points, scalars, ctx);\n    BN_CTX_free(new_ctx);\n    return ret;\n}', 'int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)\n{\n    int ret = bn_mul_fixed_top(r, a, b, ctx);\n    bn_correct_top(r);\n    bn_check_top(r);\n    return ret;\n}', 'int bn_mul_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)\n{\n    int ret = 0;\n    int top, al, bl;\n    BIGNUM *rr;\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n    int i;\n#endif\n#ifdef BN_RECURSION\n    BIGNUM *t = NULL;\n    int j = 0, k;\n#endif\n    bn_check_top(a);\n    bn_check_top(b);\n    bn_check_top(r);\n    al = a->top;\n    bl = b->top;\n    if ((al == 0) || (bl == 0)) {\n        BN_zero(r);\n        return 1;\n    }\n    top = al + bl;\n    BN_CTX_start(ctx);\n    if ((r == a) || (r == b)) {\n        if ((rr = BN_CTX_get(ctx)) == NULL)\n            goto err;\n    } else\n        rr = r;\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n    i = al - bl;\n#endif\n#ifdef BN_MUL_COMBA\n    if (i == 0) {\n# if 0\n        if (al == 4) {\n            if (bn_wexpand(rr, 8) == NULL)\n                goto err;\n            rr->top = 8;\n            bn_mul_comba4(rr->d, a->d, b->d);\n            goto end;\n        }\n# endif\n        if (al == 8) {\n            if (bn_wexpand(rr, 16) == NULL)\n                goto err;\n            rr->top = 16;\n            bn_mul_comba8(rr->d, a->d, b->d);\n            goto end;\n        }\n    }\n#endif\n#ifdef BN_RECURSION\n    if ((al >= BN_MULL_SIZE_NORMAL) && (bl >= BN_MULL_SIZE_NORMAL)) {\n        if (i >= -1 && i <= 1) {\n            if (i >= 0) {\n                j = BN_num_bits_word((BN_ULONG)al);\n            }\n            if (i == -1) {\n                j = BN_num_bits_word((BN_ULONG)bl);\n            }\n            j = 1 << (j - 1);\n            assert(j <= al || j <= bl);\n            k = j + j;\n            t = BN_CTX_get(ctx);\n            if (t == NULL)\n                goto err;\n            if (al > j || bl > j) {\n                if (bn_wexpand(t, k * 4) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 4) == NULL)\n                    goto err;\n                bn_mul_part_recursive(rr->d, a->d, b->d,\n                                      j, al - j, bl - j, t->d);\n            } else {\n                if (bn_wexpand(t, k * 2) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 2) == NULL)\n                    goto err;\n                bn_mul_recursive(rr->d, a->d, b->d, j, al - j, bl - j, t->d);\n            }\n            rr->top = top;\n            goto end;\n        }\n    }\n#endif\n    if (bn_wexpand(rr, top) == NULL)\n        goto err;\n    rr->top = top;\n    bn_mul_normal(rr->d, a->d, al, b->d, bl);\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n end:\n#endif\n    rr->neg = a->neg ^ b->neg;\n    rr->flags |= BN_FLG_FIXED_TOP;\n    if (r != rr && BN_copy(r, rr) == NULL)\n        goto err;\n    ret = 1;\n err:\n    bn_check_top(r);\n    BN_CTX_end(ctx);\n    return ret;\n}', 'void BN_CTX_start(BN_CTX *ctx)\n{\n    CTXDBG("ENTER BN_CTX_start()", ctx);\n    if (ctx->err_stack || ctx->too_many)\n        ctx->err_stack++;\n    else if (!BN_STACK_push(&ctx->stack, ctx->used)) {\n        BNerr(BN_F_BN_CTX_START, BN_R_TOO_MANY_TEMPORARY_VARIABLES);\n        ctx->err_stack++;\n    }\n    CTXDBG("LEAVE BN_CTX_start()", ctx);\n}', 'void BN_CTX_end(BN_CTX *ctx)\n{\n    CTXDBG("ENTER BN_CTX_end()", ctx);\n    if (ctx->err_stack)\n        ctx->err_stack--;\n    else {\n        unsigned int fp = BN_STACK_pop(&ctx->stack);\n        if (fp < ctx->used)\n            BN_POOL_release(&ctx->pool, ctx->used - fp);\n        ctx->used = fp;\n        ctx->too_many = 0;\n    }\n    CTXDBG("LEAVE BN_CTX_end()", ctx);\n}', 'static unsigned int BN_STACK_pop(BN_STACK *st)\n{\n    return st->indexes[--(st->depth)];\n}']