static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['int ec_GF2m_simple_make_affine(const EC_GROUP *group, EC_POINT *point,\n                               BN_CTX *ctx)\n{\n    BN_CTX *new_ctx = NULL;\n    BIGNUM *x, *y;\n    int ret = 0;\n    if (point->Z_is_one || EC_POINT_is_at_infinity(group, point))\n        return 1;\n    if (ctx == NULL) {\n        ctx = new_ctx = BN_CTX_new();\n        if (ctx == NULL)\n            return 0;\n    }\n    BN_CTX_start(ctx);\n    x = BN_CTX_get(ctx);\n    y = BN_CTX_get(ctx);\n    if (y == NULL)\n        goto err;\n    if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx))\n        goto err;\n    if (!BN_copy(point->X, x))\n        goto err;\n    if (!BN_copy(point->Y, y))\n        goto err;\n    if (!BN_one(point->Z))\n        goto err;\n    point->Z_is_one = 1;\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    BN_CTX_free(new_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}']