int BN_set_word(BIGNUM *a, BN_ULONG w)
{
    bn_check_top(a);
    if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
        return (0);
    a->neg = 0;
    a->d[0] = w;
    a->top = (w ? 1 : 0);
    bn_check_top(a);
    return (1);
}
['int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)\n{\n    int ok = 0;\n    BIGNUM *tmp = NULL;\n    BN_CTX *ctx = NULL;\n    *ret = 0;\n    ctx = BN_CTX_new();\n    if (ctx == NULL)\n        goto err;\n    BN_CTX_start(ctx);\n    tmp = BN_CTX_get(ctx);\n    if (tmp == NULL || !BN_set_word(tmp, 1))\n        goto err;\n    if (BN_cmp(pub_key, tmp) <= 0)\n        *ret |= DH_CHECK_PUBKEY_TOO_SMALL;\n    if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1))\n        goto err;\n    if (BN_cmp(pub_key, tmp) >= 0)\n        *ret |= DH_CHECK_PUBKEY_TOO_LARGE;\n    if (dh->q != NULL) {\n        if (!BN_mod_exp(tmp, pub_key, dh->q, dh->p, ctx))\n            goto err;\n        if (!BN_is_one(tmp))\n            *ret |= DH_CHECK_PUBKEY_INVALID;\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}', 'BIGNUM *BN_CTX_get(BN_CTX *ctx)\n{\n    BIGNUM *ret;\n    CTXDBG_ENTRY("BN_CTX_get", ctx);\n    if (ctx->err_stack || ctx->too_many)\n        return NULL;\n    if ((ret = BN_POOL_get(&ctx->pool, ctx->flags)) == NULL) {\n        ctx->too_many = 1;\n        BNerr(BN_F_BN_CTX_GET, BN_R_TOO_MANY_TEMPORARY_VARIABLES);\n        return NULL;\n    }\n    BN_zero(ret);\n    ctx->used++;\n    CTXDBG_RET(ctx, ret);\n    return ret;\n}', 'int BN_set_word(BIGNUM *a, BN_ULONG w)\n{\n    bn_check_top(a);\n    if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)\n        return (0);\n    a->neg = 0;\n    a->d[0] = w;\n    a->top = (w ? 1 : 0);\n    bn_check_top(a);\n    return (1);\n}', 'int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,\n               BN_CTX *ctx)\n{\n    int ret;\n    bn_check_top(a);\n    bn_check_top(p);\n    bn_check_top(m);\n#define MONT_MUL_MOD\n#define MONT_EXP_WORD\n#define RECP_MUL_MOD\n#ifdef MONT_MUL_MOD\n    if (BN_is_odd(m)) {\n# ifdef MONT_EXP_WORD\n        if (a->top == 1 && !a->neg\n            && (BN_get_flags(p, BN_FLG_CONSTTIME) == 0)) {\n            BN_ULONG A = a->d[0];\n            ret = BN_mod_exp_mont_word(r, A, p, m, ctx, NULL);\n        } else\n# endif\n            ret = BN_mod_exp_mont(r, a, p, m, ctx, NULL);\n    } else\n#endif\n#ifdef RECP_MUL_MOD\n    {\n        ret = BN_mod_exp_recp(r, a, p, m, ctx);\n    }\n#else\n    {\n        ret = BN_mod_exp_simple(r, a, p, m, ctx);\n    }\n#endif\n    bn_check_top(r);\n    return (ret);\n}', 'int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p,\n                         const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont)\n{\n    BN_MONT_CTX *mont = NULL;\n    int b, bits, ret = 0;\n    int r_is_one;\n    BN_ULONG w, next_w;\n    BIGNUM *d, *r, *t;\n    BIGNUM *swap_tmp;\n#define BN_MOD_MUL_WORD(r, w, m) \\\n                (BN_mul_word(r, (w)) && \\\n                (   \\\n                        (BN_mod(t, r, m, ctx) && (swap_tmp = r, r = t, t = swap_tmp, 1))))\n#define BN_TO_MONTGOMERY_WORD(r, w, mont) \\\n                (BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont), ctx))\n    if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0) {\n        BNerr(BN_F_BN_MOD_EXP_MONT_WORD, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);\n        return -1;\n    }\n    bn_check_top(p);\n    bn_check_top(m);\n    if (!BN_is_odd(m)) {\n        BNerr(BN_F_BN_MOD_EXP_MONT_WORD, BN_R_CALLED_WITH_EVEN_MODULUS);\n        return (0);\n    }\n    if (m->top == 1)\n        a %= m->d[0];\n    bits = BN_num_bits(p);\n    if (bits == 0) {\n        if (BN_is_one(m)) {\n            ret = 1;\n            BN_zero(rr);\n        } else {\n            ret = BN_one(rr);\n        }\n        return ret;\n    }\n    if (a == 0) {\n        BN_zero(rr);\n        ret = 1;\n        return ret;\n    }\n    BN_CTX_start(ctx);\n    d = BN_CTX_get(ctx);\n    r = BN_CTX_get(ctx);\n    t = BN_CTX_get(ctx);\n    if (d == NULL || r == NULL || t == 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    r_is_one = 1;\n    w = a;\n    for (b = bits - 2; b >= 0; b--) {\n        next_w = w * w;\n        if ((next_w / w) != w) {\n            if (r_is_one) {\n                if (!BN_TO_MONTGOMERY_WORD(r, w, mont))\n                    goto err;\n                r_is_one = 0;\n            } else {\n                if (!BN_MOD_MUL_WORD(r, w, m))\n                    goto err;\n            }\n            next_w = 1;\n        }\n        w = next_w;\n        if (!r_is_one) {\n            if (!BN_mod_mul_montgomery(r, r, r, mont, ctx))\n                goto err;\n        }\n        if (BN_is_bit_set(p, b)) {\n            next_w = w * a;\n            if ((next_w / a) != w) {\n                if (r_is_one) {\n                    if (!BN_TO_MONTGOMERY_WORD(r, w, mont))\n                        goto err;\n                    r_is_one = 0;\n                } else {\n                    if (!BN_MOD_MUL_WORD(r, w, m))\n                        goto err;\n                }\n                next_w = a;\n            }\n            w = next_w;\n        }\n    }\n    if (w != 1) {\n        if (r_is_one) {\n            if (!BN_TO_MONTGOMERY_WORD(r, w, mont))\n                goto err;\n            r_is_one = 0;\n        } else {\n            if (!BN_MOD_MUL_WORD(r, w, m))\n                goto err;\n        }\n    }\n    if (r_is_one) {\n        if (!BN_one(rr))\n            goto err;\n    } else {\n        if (!BN_from_montgomery(rr, r, mont, ctx))\n            goto err;\n    }\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}']