static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
{
    BN_ULONG *a = NULL;
    if (words > (INT_MAX / (4 * BN_BITS2))) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);
        return NULL;
    }
    if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
        return NULL;
    }
    if (BN_get_flags(b, BN_FLG_SECURE))
        a = OPENSSL_secure_zalloc(words * sizeof(*a));
    else
        a = OPENSSL_zalloc(words * sizeof(*a));
    if (a == NULL) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    assert(b->top <= words);
    if (b->top > 0)
        memcpy(a, b->d, sizeof(*a) * b->top);
    return a;
}
['int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,\n                    const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont)\n{\n    int i, j, bits, ret = 0, wstart, wend, window, wvalue;\n    int start = 1;\n    BIGNUM *d, *r;\n    const BIGNUM *aa;\n    BIGNUM *val[TABLE_SIZE];\n    BN_MONT_CTX *mont = NULL;\n    if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0\n            || BN_get_flags(a, BN_FLG_CONSTTIME) != 0\n            || BN_get_flags(m, BN_FLG_CONSTTIME) != 0) {\n        return BN_mod_exp_mont_consttime(rr, a, p, m, ctx, in_mont);\n    }\n    bn_check_top(a);\n    bn_check_top(p);\n    bn_check_top(m);\n    if (!BN_is_odd(m)) {\n        BNerr(BN_F_BN_MOD_EXP_MONT, BN_R_CALLED_WITH_EVEN_MODULUS);\n        return 0;\n    }\n    bits = BN_num_bits(p);\n    if (bits == 0) {\n        if (BN_abs_is_word(m, 1)) {\n            ret = 1;\n            BN_zero(rr);\n        } else {\n            ret = BN_one(rr);\n        }\n        return ret;\n    }\n    BN_CTX_start(ctx);\n    d = BN_CTX_get(ctx);\n    r = BN_CTX_get(ctx);\n    val[0] = BN_CTX_get(ctx);\n    if (val[0] == NULL)\n        goto err;\n    if (in_mont != NULL)\n        mont = in_mont;\n    else {\n        if ((mont = BN_MONT_CTX_new()) == NULL)\n            goto err;\n        if (!BN_MONT_CTX_set(mont, m, ctx))\n            goto err;\n    }\n    if (a->neg || BN_ucmp(a, m) >= 0) {\n        if (!BN_nnmod(val[0], a, m, ctx))\n            goto err;\n        aa = val[0];\n    } else\n        aa = a;\n    if (!bn_to_mont_fixed_top(val[0], aa, mont, ctx))\n        goto err;\n    window = BN_window_bits_for_exponent_size(bits);\n    if (window > 1) {\n        if (!bn_mul_mont_fixed_top(d, val[0], val[0], mont, ctx))\n            goto err;\n        j = 1 << (window - 1);\n        for (i = 1; i < j; i++) {\n            if (((val[i] = BN_CTX_get(ctx)) == NULL) ||\n                !bn_mul_mont_fixed_top(val[i], val[i - 1], d, mont, ctx))\n                goto err;\n        }\n    }\n    start = 1;\n    wvalue = 0;\n    wstart = bits - 1;\n    wend = 0;\n#if 1\n    j = m->top;\n    if (m->d[j - 1] & (((BN_ULONG)1) << (BN_BITS2 - 1))) {\n        if (bn_wexpand(r, j) == NULL)\n            goto err;\n        r->d[0] = (0 - m->d[0]) & BN_MASK2;\n        for (i = 1; i < j; i++)\n            r->d[i] = (~m->d[i]) & BN_MASK2;\n        r->top = j;\n        r->flags |= BN_FLG_FIXED_TOP;\n    } else\n#endif\n    if (!bn_to_mont_fixed_top(r, BN_value_one(), mont, ctx))\n        goto err;\n    for (;;) {\n        if (BN_is_bit_set(p, wstart) == 0) {\n            if (!start) {\n                if (!bn_mul_mont_fixed_top(r, r, r, mont, ctx))\n                    goto err;\n            }\n            if (wstart == 0)\n                break;\n            wstart--;\n            continue;\n        }\n        j = wstart;\n        wvalue = 1;\n        wend = 0;\n        for (i = 1; i < window; i++) {\n            if (wstart - i < 0)\n                break;\n            if (BN_is_bit_set(p, wstart - i)) {\n                wvalue <<= (i - wend);\n                wvalue |= 1;\n                wend = i;\n            }\n        }\n        j = wend + 1;\n        if (!start)\n            for (i = 0; i < j; i++) {\n                if (!bn_mul_mont_fixed_top(r, r, r, mont, ctx))\n                    goto err;\n            }\n        if (!bn_mul_mont_fixed_top(r, r, val[wvalue >> 1], mont, ctx))\n            goto err;\n        wstart -= wend + 1;\n        wvalue = 0;\n        start = 0;\n        if (wstart < 0)\n            break;\n    }\n#if defined(SPARC_T4_MONT)\n    if (OPENSSL_sparcv9cap_P[0] & (SPARCV9_VIS3 | SPARCV9_PREFER_FPU)) {\n        j = mont->N.top;\n        val[0]->d[0] = 1;\n        for (i = 1; i < j; i++)\n            val[0]->d[i] = 0;\n        val[0]->top = j;\n        if (!BN_mod_mul_montgomery(rr, r, val[0], mont, ctx))\n            goto err;\n    } else\n#endif\n    if (!BN_from_montgomery(rr, r, mont, ctx))\n        goto err;\n    ret = 1;\n err:\n    if (in_mont == NULL)\n        BN_MONT_CTX_free(mont);\n    BN_CTX_end(ctx);\n    bn_check_top(rr);\n    return ret;\n}', 'int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)\n{\n    int i, ret = 0;\n    BIGNUM *Ri, *R;\n    if (BN_is_zero(mod))\n        return 0;\n    BN_CTX_start(ctx);\n    if ((Ri = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    R = &(mont->RR);\n    if (!BN_copy(&(mont->N), mod))\n        goto err;\n    if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)\n        BN_set_flags(&(mont->N), BN_FLG_CONSTTIME);\n    mont->N.neg = 0;\n#ifdef MONT_WORD\n    {\n        BIGNUM tmod;\n        BN_ULONG buf[2];\n        bn_init(&tmod);\n        tmod.d = buf;\n        tmod.dmax = 2;\n        tmod.neg = 0;\n        if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)\n            BN_set_flags(&tmod, BN_FLG_CONSTTIME);\n        mont->ri = (BN_num_bits(mod) + (BN_BITS2 - 1)) / BN_BITS2 * BN_BITS2;\n# if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)\n        BN_zero(R);\n        if (!(BN_set_bit(R, 2 * BN_BITS2)))\n            goto err;\n        tmod.top = 0;\n        if ((buf[0] = mod->d[0]))\n            tmod.top = 1;\n        if ((buf[1] = mod->top > 1 ? mod->d[1] : 0))\n            tmod.top = 2;\n        if (BN_is_one(&tmod))\n            BN_zero(Ri);\n        else if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL)\n            goto err;\n        if (!BN_lshift(Ri, Ri, 2 * BN_BITS2))\n            goto err;\n        if (!BN_is_zero(Ri)) {\n            if (!BN_sub_word(Ri, 1))\n                goto err;\n        } else {\n            if (bn_expand(Ri, (int)sizeof(BN_ULONG) * 2) == NULL)\n                goto err;\n            Ri->neg = 0;\n            Ri->d[0] = BN_MASK2;\n            Ri->d[1] = BN_MASK2;\n            Ri->top = 2;\n        }\n        if (!BN_div(Ri, NULL, Ri, &tmod, ctx))\n            goto err;\n        mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;\n        mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0;\n# else\n        BN_zero(R);\n        if (!(BN_set_bit(R, BN_BITS2)))\n            goto err;\n        buf[0] = mod->d[0];\n        buf[1] = 0;\n        tmod.top = buf[0] != 0 ? 1 : 0;\n        if (BN_is_one(&tmod))\n            BN_zero(Ri);\n        else if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL)\n            goto err;\n        if (!BN_lshift(Ri, Ri, BN_BITS2))\n            goto err;\n        if (!BN_is_zero(Ri)) {\n            if (!BN_sub_word(Ri, 1))\n                goto err;\n        } else {\n            if (!BN_set_word(Ri, BN_MASK2))\n                goto err;\n        }\n        if (!BN_div(Ri, NULL, Ri, &tmod, ctx))\n            goto err;\n        mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;\n        mont->n0[1] = 0;\n# endif\n    }\n#else\n    {\n        mont->ri = BN_num_bits(&mont->N);\n        BN_zero(R);\n        if (!BN_set_bit(R, mont->ri))\n            goto err;\n        if ((BN_mod_inverse(Ri, R, &mont->N, ctx)) == NULL)\n            goto err;\n        if (!BN_lshift(Ri, Ri, mont->ri))\n            goto err;\n        if (!BN_sub_word(Ri, 1))\n            goto err;\n        if (!BN_div(&(mont->Ni), NULL, Ri, &mont->N, ctx))\n            goto err;\n    }\n#endif\n    BN_zero(&(mont->RR));\n    if (!BN_set_bit(&(mont->RR), mont->ri * 2))\n        goto err;\n    if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx))\n        goto err;\n    for (i = mont->RR.top, ret = mont->N.top; i < ret; i++)\n        mont->RR.d[i] = 0;\n    mont->RR.top = ret;\n    mont->RR.flags |= BN_FLG_FIXED_TOP;\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)\n{\n    int ret;\n    if (n < 0) {\n        BNerr(BN_F_BN_LSHIFT, BN_R_INVALID_SHIFT);\n        return 0;\n    }\n    ret = bn_lshift_fixed_top(r, a, n);\n    bn_correct_top(r);\n    bn_check_top(r);\n    return ret;\n}', 'int BN_nnmod(BIGNUM *r, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)\n{\n    if (!(BN_mod(r, m, d, ctx)))\n        return 0;\n    if (!r->neg)\n        return 1;\n    return (d->neg ? BN_sub : BN_add) (r, r, d);\n}', 'int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,\n           BN_CTX *ctx)\n{\n    int ret;\n    if (BN_is_zero(divisor)) {\n        BNerr(BN_F_BN_DIV, BN_R_DIV_BY_ZERO);\n        return 0;\n    }\n    if (divisor->d[divisor->top - 1] == 0) {\n        BNerr(BN_F_BN_DIV, BN_R_NOT_INITIALIZED);\n        return 0;\n    }\n    ret = bn_div_fixed_top(dv, rm, num, divisor, ctx);\n    if (ret) {\n        if (dv != NULL)\n            bn_correct_top(dv);\n        if (rm != NULL)\n            bn_correct_top(rm);\n    }\n    return ret;\n}', 'int bn_div_fixed_top(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,\n                     const BIGNUM *divisor, BN_CTX *ctx)\n{\n    int norm_shift, i, j, loop;\n    BIGNUM *tmp, *snum, *sdiv, *res;\n    BN_ULONG *resp, *wnum, *wnumtop;\n    BN_ULONG d0, d1;\n    int num_n, div_n;\n    assert(divisor->top > 0 && divisor->d[divisor->top - 1] != 0);\n    bn_check_top(num);\n    bn_check_top(divisor);\n    bn_check_top(dv);\n    bn_check_top(rm);\n    BN_CTX_start(ctx);\n    res = (dv == NULL) ? BN_CTX_get(ctx) : dv;\n    tmp = BN_CTX_get(ctx);\n    snum = BN_CTX_get(ctx);\n    sdiv = BN_CTX_get(ctx);\n    if (sdiv == NULL)\n        goto err;\n    if (!BN_copy(sdiv, divisor))\n        goto err;\n    norm_shift = bn_left_align(sdiv);\n    sdiv->neg = 0;\n    if (!(bn_lshift_fixed_top(snum, num, norm_shift)))\n        goto err;\n    div_n = sdiv->top;\n    num_n = snum->top;\n    if (num_n <= div_n) {\n        if (bn_wexpand(snum, div_n + 1) == NULL)\n            goto err;\n        memset(&(snum->d[num_n]), 0, (div_n - num_n + 1) * sizeof(BN_ULONG));\n        snum->top = num_n = div_n + 1;\n    }\n    loop = num_n - div_n;\n    wnum = &(snum->d[loop]);\n    wnumtop = &(snum->d[num_n - 1]);\n    d0 = sdiv->d[div_n - 1];\n    d1 = (div_n == 1) ? 0 : sdiv->d[div_n - 2];\n    if (!bn_wexpand(res, loop))\n        goto err;\n    res->neg = (num->neg ^ divisor->neg);\n    res->top = loop;\n    res->flags |= BN_FLG_FIXED_TOP;\n    resp = &(res->d[loop]);\n    if (!bn_wexpand(tmp, (div_n + 1)))\n        goto err;\n    for (i = 0; i < loop; i++, wnumtop--) {\n        BN_ULONG q, l0;\n# if defined(BN_DIV3W)\n        q = bn_div_3_words(wnumtop, d1, d0);\n# else\n        BN_ULONG n0, n1, rem = 0;\n        n0 = wnumtop[0];\n        n1 = wnumtop[-1];\n        if (n0 == d0)\n            q = BN_MASK2;\n        else {\n            BN_ULONG n2 = (wnumtop == wnum) ? 0 : wnumtop[-2];\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) | n2))\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 <= n2)))\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--;\n        l0 = bn_sub_words(wnum, wnum, tmp->d, div_n + 1);\n        q -= l0;\n        for (l0 = 0 - l0, j = 0; j < div_n; j++)\n            tmp->d[j] = sdiv->d[j] & l0;\n        l0 = bn_add_words(wnum, wnum, tmp->d, div_n);\n        (*wnumtop) += l0;\n        assert((*wnumtop) == 0);\n        *--resp = q;\n    }\n    snum->neg = num->neg;\n    snum->top = div_n;\n    snum->flags |= BN_FLG_FIXED_TOP;\n    if (rm != NULL)\n        bn_rshift_fixed_top(rm, snum, norm_shift);\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_rshift_fixed_top(BIGNUM *r, const BIGNUM *a, int n)\n{\n    int i, top, nw;\n    unsigned int lb, rb;\n    BN_ULONG *t, *f;\n    BN_ULONG l, m, mask;\n    bn_check_top(r);\n    bn_check_top(a);\n    assert(n >= 0);\n    nw = n / BN_BITS2;\n    if (nw >= a->top) {\n        BN_zero(r);\n        return 1;\n    }\n    rb = (unsigned int)n % BN_BITS2;\n    lb = BN_BITS2 - rb;\n    lb %= BN_BITS2;\n    mask = (BN_ULONG)0 - lb;\n    mask |= mask >> 8;\n    top = a->top - nw;\n    if (r != a && bn_wexpand(r, top) == NULL)\n        return 0;\n    t = &(r->d[0]);\n    f = &(a->d[nw]);\n    l = f[0];\n    for (i = 0; i < top - 1; i++) {\n        m = f[i + 1];\n        t[i] = (l >> rb) | ((m << lb) & mask);\n        l = m;\n    }\n    t[i] = l >> rb;\n    r->neg = a->neg;\n    r->top = top;\n    r->flags |= BN_FLG_FIXED_TOP;\n    return 1;\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}', 'BIGNUM *bn_expand2(BIGNUM *b, int words)\n{\n    if (words > b->dmax) {\n        BN_ULONG *a = bn_expand_internal(b, words);\n        if (!a)\n            return NULL;\n        if (b->d) {\n            OPENSSL_cleanse(b->d, b->dmax * sizeof(b->d[0]));\n            bn_free_d(b);\n        }\n        b->d = a;\n        b->dmax = words;\n    }\n    return b;\n}', 'static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)\n{\n    BN_ULONG *a = NULL;\n    if (words > (INT_MAX / (4 * BN_BITS2))) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);\n        return NULL;\n    }\n    if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);\n        return NULL;\n    }\n    if (BN_get_flags(b, BN_FLG_SECURE))\n        a = OPENSSL_secure_zalloc(words * sizeof(*a));\n    else\n        a = OPENSSL_zalloc(words * sizeof(*a));\n    if (a == NULL) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);\n        return NULL;\n    }\n    assert(b->top <= words);\n    if (b->top > 0)\n        memcpy(a, b->d, sizeof(*a) * b->top);\n    return a;\n}']