static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['static int dsa_builtin_keygen(DSA *dsa)\n{\n    int ok = 0;\n    BN_CTX *ctx = NULL;\n    BIGNUM *pub_key = NULL, *priv_key = NULL;\n    if ((ctx = BN_CTX_new()) == NULL)\n        goto err;\n    if (dsa->priv_key == NULL) {\n        if ((priv_key = BN_secure_new()) == NULL)\n            goto err;\n    } else\n        priv_key = dsa->priv_key;\n    do\n        if (!BN_priv_rand_range(priv_key, dsa->q))\n            goto err;\n    while (BN_is_zero(priv_key)) ;\n    if (dsa->pub_key == NULL) {\n        if ((pub_key = BN_new()) == NULL)\n            goto err;\n    } else\n        pub_key = dsa->pub_key;\n    {\n        BIGNUM *prk = BN_new();\n        if (prk == NULL)\n            goto err;\n        BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);\n        if (!BN_mod_exp(pub_key, dsa->g, prk, dsa->p, ctx)) {\n            BN_free(prk);\n            goto err;\n        }\n        BN_free(prk);\n    }\n    dsa->priv_key = priv_key;\n    dsa->pub_key = pub_key;\n    ok = 1;\n err:\n    if (pub_key != dsa->pub_key)\n        BN_free(pub_key);\n    if (priv_key != dsa->priv_key)\n        BN_free(priv_key);\n    BN_CTX_free(ctx);\n    return ok;\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_get_flags(a, BN_FLG_CONSTTIME) == 0)\n            && (BN_get_flags(m, 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_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,\n                    const BIGNUM *m, BN_CTX *ctx)\n{\n    int i, j, bits, ret = 0, wstart, wend, window, wvalue;\n    int start = 1;\n    BIGNUM *aa;\n    BIGNUM *val[TABLE_SIZE];\n    BN_RECP_CTX recp;\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        BNerr(BN_F_BN_MOD_EXP_RECP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);\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(r);\n        } else {\n            ret = BN_one(r);\n        }\n        return ret;\n    }\n    BN_CTX_start(ctx);\n    aa = BN_CTX_get(ctx);\n    val[0] = BN_CTX_get(ctx);\n    if (val[0] == NULL)\n        goto err;\n    BN_RECP_CTX_init(&recp);\n    if (m->neg) {\n        if (!BN_copy(aa, m))\n            goto err;\n        aa->neg = 0;\n        if (BN_RECP_CTX_set(&recp, aa, ctx) <= 0)\n            goto err;\n    } else {\n        if (BN_RECP_CTX_set(&recp, m, ctx) <= 0)\n            goto err;\n    }\n    if (!BN_nnmod(val[0], a, m, ctx))\n        goto err;\n    if (BN_is_zero(val[0])) {\n        BN_zero(r);\n        ret = 1;\n        goto err;\n    }\n    window = BN_window_bits_for_exponent_size(bits);\n    if (window > 1) {\n        if (!BN_mod_mul_reciprocal(aa, val[0], val[0], &recp, 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_mod_mul_reciprocal(val[i], val[i - 1], aa, &recp, ctx))\n                goto err;\n        }\n    }\n    start = 1;\n    wvalue = 0;\n    wstart = bits - 1;\n    wend = 0;\n    if (!BN_one(r))\n        goto err;\n    for (;;) {\n        if (BN_is_bit_set(p, wstart) == 0) {\n            if (!start)\n                if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx))\n                    goto err;\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_mod_mul_reciprocal(r, r, r, &recp, ctx))\n                    goto err;\n            }\n        if (!BN_mod_mul_reciprocal(r, r, val[wvalue >> 1], &recp, ctx))\n            goto err;\n        wstart -= wend + 1;\n        wvalue = 0;\n        start = 0;\n        if (wstart < 0)\n            break;\n    }\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    BN_RECP_CTX_free(&recp);\n    bn_check_top(r);\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}', 'BIGNUM *BN_CTX_get(BN_CTX *ctx)\n{\n    BIGNUM *ret;\n    CTXDBG("ENTER 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    ret->flags &= (~BN_FLG_CONSTTIME);\n    ctx->used++;\n    CTXDBG("LEAVE BN_CTX_get()", ctx);\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_mod_mul_reciprocal(BIGNUM *r, const BIGNUM *x, const BIGNUM *y,\n                          BN_RECP_CTX *recp, BN_CTX *ctx)\n{\n    int ret = 0;\n    BIGNUM *a;\n    const BIGNUM *ca;\n    BN_CTX_start(ctx);\n    if ((a = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    if (y != NULL) {\n        if (x == y) {\n            if (!BN_sqr(a, x, ctx))\n                goto err;\n        } else {\n            if (!BN_mul(a, x, y, ctx))\n                goto err;\n        }\n        ca = a;\n    } else\n        ca = x;\n    ret = BN_div_recp(NULL, r, ca, recp, ctx);\n err:\n    BN_CTX_end(ctx);\n    bn_check_top(r);\n    return ret;\n}', 'int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,\n                BN_RECP_CTX *recp, BN_CTX *ctx)\n{\n    int i, j, ret = 0;\n    BIGNUM *a, *b, *d, *r;\n    BN_CTX_start(ctx);\n    d = (dv != NULL) ? dv : BN_CTX_get(ctx);\n    r = (rem != NULL) ? rem : BN_CTX_get(ctx);\n    a = BN_CTX_get(ctx);\n    b = BN_CTX_get(ctx);\n    if (b == NULL)\n        goto err;\n    if (BN_ucmp(m, &(recp->N)) < 0) {\n        BN_zero(d);\n        if (!BN_copy(r, m)) {\n            BN_CTX_end(ctx);\n            return 0;\n        }\n        BN_CTX_end(ctx);\n        return 1;\n    }\n    i = BN_num_bits(m);\n    j = recp->num_bits << 1;\n    if (j > i)\n        i = j;\n    if (i != recp->shift)\n        recp->shift = BN_reciprocal(&(recp->Nr), &(recp->N), i, ctx);\n    if (recp->shift == -1)\n        goto err;\n    if (!BN_rshift(a, m, recp->num_bits))\n        goto err;\n    if (!BN_mul(b, a, &(recp->Nr), ctx))\n        goto err;\n    if (!BN_rshift(d, b, i - recp->num_bits))\n        goto err;\n    d->neg = 0;\n    if (!BN_mul(b, &(recp->N), d, ctx))\n        goto err;\n    if (!BN_usub(r, m, b))\n        goto err;\n    r->neg = 0;\n    j = 0;\n    while (BN_ucmp(r, &(recp->N)) >= 0) {\n        if (j++ > 2) {\n            BNerr(BN_F_BN_DIV_RECP, BN_R_BAD_RECIPROCAL);\n            goto err;\n        }\n        if (!BN_usub(r, r, &(recp->N)))\n            goto err;\n        if (!BN_add_word(d, 1))\n            goto err;\n    }\n    r->neg = BN_is_zero(r) ? 0 : m->neg;\n    d->neg = m->neg ^ recp->N.neg;\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    bn_check_top(dv);\n    bn_check_top(rem);\n    return ret;\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}']