int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
{
    int i, nw, lb, rb;
    BN_ULONG *t, *f;
    BN_ULONG l;
    bn_check_top(r);
    bn_check_top(a);
    if (n < 0) {
        BNerr(BN_F_BN_LSHIFT, BN_R_INVALID_SHIFT);
        return 0;
    }
    nw = n / BN_BITS2;
    if (bn_wexpand(r, a->top + nw + 1) == NULL)
        return (0);
    r->neg = a->neg;
    lb = n % BN_BITS2;
    rb = BN_BITS2 - lb;
    f = a->d;
    t = r->d;
    t[a->top + nw] = 0;
    if (lb == 0)
        for (i = a->top - 1; i >= 0; i--)
            t[nw + i] = f[i];
    else
        for (i = a->top - 1; i >= 0; i--) {
            l = f[i];
            t[nw + i + 1] |= (l >> rb) & BN_MASK2;
            t[nw + i] = (l << lb) & BN_MASK2;
        }
    memset(t, 0, sizeof(*t) * nw);
    r->top = a->top + nw + 1;
    bn_correct_top(r);
    bn_check_top(r);
    return (1);
}
['static int dh_test(void)\n{\n    BN_GENCB *_cb = NULL;\n    DH *a = NULL;\n    DH *b = NULL;\n    const BIGNUM *ap = NULL, *ag = NULL, *apub_key = NULL;\n    const BIGNUM *bpub_key = NULL;\n    BIGNUM *bp = NULL, *bg = NULL;\n    unsigned char *abuf = NULL;\n    unsigned char *bbuf = NULL;\n    int i, alen, blen, aout, bout;\n    int ret = 0;\n    RAND_seed(rnd_seed, sizeof rnd_seed);\n    if (!TEST_ptr(_cb = BN_GENCB_new()))\n        goto err;\n    BN_GENCB_set(_cb, &cb, NULL);\n    if (!TEST_ptr(a = DH_new())\n            || !TEST_true(DH_generate_parameters_ex(a, 64,\n                                                    DH_GENERATOR_5, _cb)))\n        goto err;\n    if (!DH_check(a, &i))\n        goto err;\n    if (!TEST_false(i & DH_CHECK_P_NOT_PRIME)\n            || !TEST_false(i & DH_CHECK_P_NOT_SAFE_PRIME)\n            || !TEST_false(i & DH_UNABLE_TO_CHECK_GENERATOR)\n            || !TEST_false(i & DH_NOT_SUITABLE_GENERATOR))\n        goto err;\n    DH_get0_pqg(a, &ap, NULL, &ag);\n    if (!TEST_ptr(b = DH_new()))\n        goto err;\n    if (!TEST_ptr(bp = BN_dup(ap))\n            || !TEST_ptr(bg = BN_dup(ag))\n            || !TEST_true(DH_set0_pqg(b, bp, NULL, bg)))\n        goto err;\n    bp = bg = NULL;\n    if (!DH_generate_key(a))\n        goto err;\n    DH_get0_key(a, &apub_key, NULL);\n    if (!DH_generate_key(b))\n        goto err;\n    DH_get0_key(b, &bpub_key, NULL);\n    alen = DH_size(a);\n    if (!TEST_ptr(abuf = OPENSSL_malloc(alen))\n            || !TEST_true((aout = DH_compute_key(abuf, bpub_key, a)) != -1))\n        goto err;\n    blen = DH_size(b);\n    if (!TEST_ptr(bbuf = OPENSSL_malloc(blen))\n            || !TEST_true((bout = DH_compute_key(bbuf, apub_key, b)) != -1))\n        goto err;\n    if (!TEST_true(aout >= 4)\n            || !TEST_mem_eq(abuf, aout, bbuf, bout))\n        goto err;\n    ret = 1;\n err:\n    OPENSSL_free(abuf);\n    OPENSSL_free(bbuf);\n    DH_free(b);\n    DH_free(a);\n    BN_free(bp);\n    BN_free(bg);\n    BN_GENCB_free(_cb);\n    return ret;\n}', 'int DH_generate_parameters_ex(DH *ret, int prime_len, int generator,\n                              BN_GENCB *cb)\n{\n    if (ret->meth->generate_params)\n        return ret->meth->generate_params(ret, prime_len, generator, cb);\n    return dh_builtin_genparams(ret, prime_len, generator, cb);\n}', 'int DH_check(const DH *dh, int *ret)\n{\n    int ok = 0, r;\n    BN_CTX *ctx = NULL;\n    BN_ULONG l;\n    BIGNUM *t1 = NULL, *t2 = NULL;\n    *ret = 0;\n    ctx = BN_CTX_new();\n    if (ctx == NULL)\n        goto err;\n    BN_CTX_start(ctx);\n    t1 = BN_CTX_get(ctx);\n    if (t1 == NULL)\n        goto err;\n    t2 = BN_CTX_get(ctx);\n    if (t2 == NULL)\n        goto err;\n    if (dh->q) {\n        if (BN_cmp(dh->g, BN_value_one()) <= 0)\n            *ret |= DH_NOT_SUITABLE_GENERATOR;\n        else if (BN_cmp(dh->g, dh->p) >= 0)\n            *ret |= DH_NOT_SUITABLE_GENERATOR;\n        else {\n            if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx))\n                goto err;\n            if (!BN_is_one(t1))\n                *ret |= DH_NOT_SUITABLE_GENERATOR;\n        }\n        r = BN_is_prime_ex(dh->q, BN_prime_checks, ctx, NULL);\n        if (r < 0)\n            goto err;\n        if (!r)\n            *ret |= DH_CHECK_Q_NOT_PRIME;\n        if (!BN_div(t1, t2, dh->p, dh->q, ctx))\n            goto err;\n        if (!BN_is_one(t2))\n            *ret |= DH_CHECK_INVALID_Q_VALUE;\n        if (dh->j && BN_cmp(dh->j, t1))\n            *ret |= DH_CHECK_INVALID_J_VALUE;\n    } else if (BN_is_word(dh->g, DH_GENERATOR_2)) {\n        l = BN_mod_word(dh->p, 24);\n        if (l == (BN_ULONG)-1)\n            goto err;\n        if (l != 11)\n            *ret |= DH_NOT_SUITABLE_GENERATOR;\n    } else if (BN_is_word(dh->g, DH_GENERATOR_5)) {\n        l = BN_mod_word(dh->p, 10);\n        if (l == (BN_ULONG)-1)\n            goto err;\n        if ((l != 3) && (l != 7))\n            *ret |= DH_NOT_SUITABLE_GENERATOR;\n    } else\n        *ret |= DH_UNABLE_TO_CHECK_GENERATOR;\n    r = BN_is_prime_ex(dh->p, BN_prime_checks, ctx, NULL);\n    if (r < 0)\n        goto err;\n    if (!r)\n        *ret |= DH_CHECK_P_NOT_PRIME;\n    else if (!dh->q) {\n        if (!BN_rshift1(t1, dh->p))\n            goto err;\n        r = BN_is_prime_ex(t1, BN_prime_checks, ctx, NULL);\n        if (r < 0)\n            goto err;\n        if (!r)\n            *ret |= DH_CHECK_P_NOT_SAFE_PRIME;\n    }\n    ok = 1;\n err:\n    if (ctx != NULL) {\n        BN_CTX_end(ctx);\n        BN_CTX_free(ctx);\n    }\n    return (ok);\n}', 'int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,\n           BN_CTX *ctx)\n{\n    int norm_shift, i, loop;\n    BIGNUM *tmp, wnum, *snum, *sdiv, *res;\n    BN_ULONG *resp, *wnump;\n    BN_ULONG d0, d1;\n    int num_n, div_n;\n    int no_branch = 0;\n    if ((num->top > 0 && num->d[num->top - 1] == 0) ||\n        (divisor->top > 0 && divisor->d[divisor->top - 1] == 0)) {\n        BNerr(BN_F_BN_DIV, BN_R_NOT_INITIALIZED);\n        return 0;\n    }\n    bn_check_top(num);\n    bn_check_top(divisor);\n    if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0)\n        || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0)) {\n        no_branch = 1;\n    }\n    bn_check_top(dv);\n    bn_check_top(rm);\n    if (BN_is_zero(divisor)) {\n        BNerr(BN_F_BN_DIV, BN_R_DIV_BY_ZERO);\n        return (0);\n    }\n    if (!no_branch && BN_ucmp(num, divisor) < 0) {\n        if (rm != NULL) {\n            if (BN_copy(rm, num) == NULL)\n                return (0);\n        }\n        if (dv != NULL)\n            BN_zero(dv);\n        return (1);\n    }\n    BN_CTX_start(ctx);\n    tmp = BN_CTX_get(ctx);\n    snum = BN_CTX_get(ctx);\n    sdiv = BN_CTX_get(ctx);\n    if (dv == NULL)\n        res = BN_CTX_get(ctx);\n    else\n        res = dv;\n    if (sdiv == NULL || res == NULL || tmp == NULL || snum == NULL)\n        goto err;\n    norm_shift = BN_BITS2 - ((BN_num_bits(divisor)) % BN_BITS2);\n    if (!(BN_lshift(sdiv, divisor, norm_shift)))\n        goto err;\n    sdiv->neg = 0;\n    norm_shift += BN_BITS2;\n    if (!(BN_lshift(snum, num, norm_shift)))\n        goto err;\n    snum->neg = 0;\n    if (no_branch) {\n        if (snum->top <= sdiv->top + 1) {\n            if (bn_wexpand(snum, sdiv->top + 2) == NULL)\n                goto err;\n            for (i = snum->top; i < sdiv->top + 2; i++)\n                snum->d[i] = 0;\n            snum->top = sdiv->top + 2;\n        } else {\n            if (bn_wexpand(snum, snum->top + 1) == NULL)\n                goto err;\n            snum->d[snum->top] = 0;\n            snum->top++;\n        }\n    }\n    div_n = sdiv->top;\n    num_n = snum->top;\n    loop = num_n - div_n;\n    wnum.neg = 0;\n    wnum.d = &(snum->d[loop]);\n    wnum.top = div_n;\n    wnum.dmax = snum->dmax - loop;\n    d0 = sdiv->d[div_n - 1];\n    d1 = (div_n == 1) ? 0 : sdiv->d[div_n - 2];\n    wnump = &(snum->d[num_n - 1]);\n    if (!bn_wexpand(res, (loop + 1)))\n        goto err;\n    res->neg = (num->neg ^ divisor->neg);\n    res->top = loop - no_branch;\n    resp = &(res->d[loop - 1]);\n    if (!bn_wexpand(tmp, (div_n + 1)))\n        goto err;\n    if (!no_branch) {\n        if (BN_ucmp(&wnum, sdiv) >= 0) {\n            bn_clear_top2max(&wnum);\n            bn_sub_words(wnum.d, wnum.d, sdiv->d, div_n);\n            *resp = 1;\n        } else\n            res->top--;\n    }\n    resp++;\n    if (res->top == 0)\n        res->neg = 0;\n    else\n        resp--;\n    for (i = 0; i < loop - 1; i++, wnump--) {\n        BN_ULONG q, l0;\n# if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM)\n        BN_ULONG bn_div_3_words(BN_ULONG *, BN_ULONG, BN_ULONG);\n        q = bn_div_3_words(wnump, d1, d0);\n# else\n        BN_ULONG n0, n1, rem = 0;\n        n0 = wnump[0];\n        n1 = wnump[-1];\n        if (n0 == d0)\n            q = BN_MASK2;\n        else {\n#  ifdef BN_LLONG\n            BN_ULLONG t2;\n#   if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words)\n            q = (BN_ULONG)(((((BN_ULLONG) n0) << BN_BITS2) | n1) / d0);\n#   else\n            q = bn_div_words(n0, n1, d0);\n#   endif\n#   ifndef REMAINDER_IS_ALREADY_CALCULATED\n            rem = (n1 - q * d0) & BN_MASK2;\n#   endif\n            t2 = (BN_ULLONG) d1 *q;\n            for (;;) {\n                if (t2 <= ((((BN_ULLONG) rem) << BN_BITS2) | wnump[-2]))\n                    break;\n                q--;\n                rem += d0;\n                if (rem < d0)\n                    break;\n                t2 -= d1;\n            }\n#  else\n            BN_ULONG t2l, t2h;\n            q = bn_div_words(n0, n1, d0);\n#   ifndef REMAINDER_IS_ALREADY_CALCULATED\n            rem = (n1 - q * d0) & BN_MASK2;\n#   endif\n#   if defined(BN_UMULT_LOHI)\n            BN_UMULT_LOHI(t2l, t2h, d1, q);\n#   elif defined(BN_UMULT_HIGH)\n            t2l = d1 * q;\n            t2h = BN_UMULT_HIGH(d1, q);\n#   else\n            {\n                BN_ULONG ql, qh;\n                t2l = LBITS(d1);\n                t2h = HBITS(d1);\n                ql = LBITS(q);\n                qh = HBITS(q);\n                mul64(t2l, t2h, ql, qh);\n            }\n#   endif\n            for (;;) {\n                if ((t2h < rem) || ((t2h == rem) && (t2l <= wnump[-2])))\n                    break;\n                q--;\n                rem += d0;\n                if (rem < d0)\n                    break;\n                if (t2l < d1)\n                    t2h--;\n                t2l -= d1;\n            }\n#  endif\n        }\n# endif\n        l0 = bn_mul_words(tmp->d, sdiv->d, div_n, q);\n        tmp->d[div_n] = l0;\n        wnum.d--;\n        if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n + 1)) {\n            q--;\n            if (bn_add_words(wnum.d, wnum.d, sdiv->d, div_n))\n                (*wnump)++;\n        }\n        resp--;\n        *resp = q;\n    }\n    bn_correct_top(snum);\n    if (rm != NULL) {\n        int neg = num->neg;\n        BN_rshift(rm, snum, norm_shift);\n        if (!BN_is_zero(rm))\n            rm->neg = neg;\n        bn_check_top(rm);\n    }\n    if (no_branch)\n        bn_correct_top(res);\n    BN_CTX_end(ctx);\n    return (1);\n err:\n    bn_check_top(rm);\n    BN_CTX_end(ctx);\n    return (0);\n}', 'int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)\n{\n    int i, nw, lb, rb;\n    BN_ULONG *t, *f;\n    BN_ULONG l;\n    bn_check_top(r);\n    bn_check_top(a);\n    if (n < 0) {\n        BNerr(BN_F_BN_LSHIFT, BN_R_INVALID_SHIFT);\n        return 0;\n    }\n    nw = n / BN_BITS2;\n    if (bn_wexpand(r, a->top + nw + 1) == NULL)\n        return (0);\n    r->neg = a->neg;\n    lb = n % BN_BITS2;\n    rb = BN_BITS2 - lb;\n    f = a->d;\n    t = r->d;\n    t[a->top + nw] = 0;\n    if (lb == 0)\n        for (i = a->top - 1; i >= 0; i--)\n            t[nw + i] = f[i];\n    else\n        for (i = a->top - 1; i >= 0; i--) {\n            l = f[i];\n            t[nw + i + 1] |= (l >> rb) & BN_MASK2;\n            t[nw + i] = (l << lb) & BN_MASK2;\n        }\n    memset(t, 0, sizeof(*t) * nw);\n    r->top = a->top + nw + 1;\n    bn_correct_top(r);\n    bn_check_top(r);\n    return (1);\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}']