Define union for Nintendo sector layout

[coderabbitai]

Background

In Nintendo disc processing (GameCube/Wii), the current code relies on guaranteed memory layout where the cpr_mai field (6 bytes) is followed by main_data, allowing safe pointer arithmetic beyond the cpr_mai array boundary.

Enhancement Request

Define a union that explicitly captures the Nintendo sector layout to make this memory access pattern type-safe and self-documenting.

References

• PR Dvd improvements #358: DVD improvements
• Discussion: Dvd improvements #358 (comment)
• File: dvd/nintendo.ixx, line 36

Requested by

@superg

cc: @superg

[Deterous]

Example:

export struct NintendoDataFrame
{
    id id;
    uint16_t ied;
    uint8_t main_data[FORM1_DATA_SIZE];
    uint8_t cpr_mai[6];
    uint32_t edc;
}