static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['int BN_GF2m_mod_solve_quad_arr(BIGNUM *r, const BIGNUM *a_, const int p[],\n                               BN_CTX *ctx)\n{\n    int ret = 0, count = 0, j;\n    BIGNUM *a, *z, *rho, *w, *w2, *tmp;\n    bn_check_top(a_);\n    if (!p[0]) {\n        BN_zero(r);\n        return 1;\n    }\n    BN_CTX_start(ctx);\n    a = BN_CTX_get(ctx);\n    z = BN_CTX_get(ctx);\n    w = BN_CTX_get(ctx);\n    if (w == NULL)\n        goto err;\n    if (!BN_GF2m_mod_arr(a, a_, p))\n        goto err;\n    if (BN_is_zero(a)) {\n        BN_zero(r);\n        ret = 1;\n        goto err;\n    }\n    if (p[0] & 0x1) {\n        if (!BN_copy(z, a))\n            goto err;\n        for (j = 1; j <= (p[0] - 1) / 2; j++) {\n            if (!BN_GF2m_mod_sqr_arr(z, z, p, ctx))\n                goto err;\n            if (!BN_GF2m_mod_sqr_arr(z, z, p, ctx))\n                goto err;\n            if (!BN_GF2m_add(z, z, a))\n                goto err;\n        }\n    } else {\n        rho = BN_CTX_get(ctx);\n        w2 = BN_CTX_get(ctx);\n        tmp = BN_CTX_get(ctx);\n        if (tmp == NULL)\n            goto err;\n        do {\n            if (!BN_priv_rand(rho, p[0], BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY))\n                goto err;\n            if (!BN_GF2m_mod_arr(rho, rho, p))\n                goto err;\n            BN_zero(z);\n            if (!BN_copy(w, rho))\n                goto err;\n            for (j = 1; j <= p[0] - 1; j++) {\n                if (!BN_GF2m_mod_sqr_arr(z, z, p, ctx))\n                    goto err;\n                if (!BN_GF2m_mod_sqr_arr(w2, w, p, ctx))\n                    goto err;\n                if (!BN_GF2m_mod_mul_arr(tmp, w2, a, p, ctx))\n                    goto err;\n                if (!BN_GF2m_add(z, z, tmp))\n                    goto err;\n                if (!BN_GF2m_add(w, w2, rho))\n                    goto err;\n            }\n            count++;\n        } while (BN_is_zero(w) && (count < MAX_ITERATIONS));\n        if (BN_is_zero(w)) {\n            BNerr(BN_F_BN_GF2M_MOD_SOLVE_QUAD_ARR, BN_R_TOO_MANY_ITERATIONS);\n            goto err;\n        }\n    }\n    if (!BN_GF2m_mod_sqr_arr(w, z, p, ctx))\n        goto err;\n    if (!BN_GF2m_add(w, z, w))\n        goto err;\n    if (BN_GF2m_cmp(w, a)) {\n        BNerr(BN_F_BN_GF2M_MOD_SOLVE_QUAD_ARR, BN_R_NO_SOLUTION);\n        goto err;\n    }\n    if (!BN_copy(r, z))\n        goto err;\n    bn_check_top(r);\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'void BN_CTX_start(BN_CTX *ctx)\n{\n    CTXDBG_ENTRY("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_EXIT(ctx);\n}', 'int BN_GF2m_mod_sqr_arr(BIGNUM *r, const BIGNUM *a, const int p[],\n                        BN_CTX *ctx)\n{\n    int i, ret = 0;\n    BIGNUM *s;\n    bn_check_top(a);\n    BN_CTX_start(ctx);\n    if ((s = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    if (!bn_wexpand(s, 2 * a->top))\n        goto err;\n    for (i = a->top - 1; i >= 0; i--) {\n        s->d[2 * i + 1] = SQR1(a->d[i]);\n        s->d[2 * i] = SQR0(a->d[i]);\n    }\n    s->top = 2 * a->top;\n    bn_correct_top(s);\n    if (!BN_GF2m_mod_arr(r, s, p))\n        goto err;\n    bn_check_top(r);\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'void BN_CTX_end(BN_CTX *ctx)\n{\n    CTXDBG_ENTRY("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_EXIT(ctx);\n}', 'static unsigned int BN_STACK_pop(BN_STACK *st)\n{\n    return st->indexes[--(st->depth)];\n}']