> For the complete documentation index, see [llms.txt](https://guide.cronuszen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guide.cronuszen.com/gpcscripting/gpc-script-guide/data-and-persistence/bvar-storage.md).

# BVAR storage

Cronus Zen provides 1,024 BVAR entries, indexed `0..1023`. Use `get_bvar(index)` to read one entry and `set_bvar(index, value)` to write one. Each entry stores a signed 16-bit word (`-32768..32767`), so validate or clamp a runtime value before writing it instead of assuming the runtime integer's wider range will persist.

{% code title="bvar-edit-value.gpc" %}

```cpp
int edit_value;

main {
    if(event_press(PS5_CROSS)) {
        edit_value = -75;
        set_bvar(120, edit_value);
    }

    if(event_press(PS5_OPTIONS)) edit_value = get_bvar(120);
    set_val(TRACE_1, edit_value);
}
```

{% endcode %}

Keep BVAR writes behind explicit edit/save events rather than the base of `main`. Read a record during initialization, profile changes, or another deliberate cache refresh instead of rescanning the complete store every cycle.

Do not scatter numeric BVAR indexes. Define a schema:

```cpp
define BVAR_SCHEMA_VERSION = 1;
define BVAR_HEADER_BASE = 0;
define BVAR_RECORD_BASE = 16;
define BVAR_RECORD_STRIDE = 8;
define BVAR_FIELD_ID = 0;
define BVAR_FIELD_LENGTH = 1;
define BVAR_FIELD_X = 2;
define BVAR_FIELD_Y = 3;
```

For record index `r`, compute:

```
base = BVAR_RECORD_BASE + r * BVAR_RECORD_STRIDE
field_index = base + BVAR_FIELD_*
```

Validate every computed index against `0..1023` and make the maximum record count a compile-time constant.


---

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