static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['int BN_GF2m_mod_div_arr(BIGNUM *r, const BIGNUM *yy, const BIGNUM *xx,\n                        const int p[], BN_CTX *ctx)\n{\n    BIGNUM *field;\n    int ret = 0;\n    bn_check_top(yy);\n    bn_check_top(xx);\n    BN_CTX_start(ctx);\n    if ((field = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    if (!BN_GF2m_arr2poly(p, field))\n        goto err;\n    ret = BN_GF2m_mod_div(r, yy, xx, field, ctx);\n    bn_check_top(r);\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}', '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}']