Enum PowerOnRam 

pub enum PowerOnRam {
    Zeroed,
    Seeded(u64),
    Filled(u8),
}

v2.1.7 P5 — power-on 2 KiB CPU work-RAM contents.

Real NES hardware powers up with unreliable RAM (nesdev “CPU power up state”); a few titles read uninitialized RAM before writing it (Final Fantasy’s RNG seed, River City Ransom, Cybernoid). This selects what pattern the work RAM (and the open-bus latch) is filled with at power-on.

Default-off / deterministic. Default (Self::Zeroed) is the established all-zero fill CI, the regression oracle, and save-state tests use; the other variants are opt-in and still fully deterministic (no wall-clock / OS RNG), so the same config + ROM + input ⇒ bit-identical contract holds.

Variants

Zeroed

Default. Work RAM + open bus power up all-zero (current behavior).

Seeded(u64)

Deterministic xorshift64 randomization keyed on the seed (the existing developer mode; see Nes::from_rom_with_power_on_seed). Surfaces software that depends on a particular post-power-on RAM pattern.

Filled(u8)

Fill every work-RAM byte (and the open-bus latch) with a single uniform byte — a documented known pattern (e.g. 0xFF, the all-ones some consoles come up with). Deterministic.

Trait Implementations

impl Clone for PowerOnRam

fn clone(&self) -> PowerOnRam

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PowerOnRam

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for PowerOnRam

fn default() -> PowerOnRam

Returns the “default value” for a type.

impl Hash for PowerOnRam

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for PowerOnRam

fn eq(&self, other: &PowerOnRam) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for PowerOnRam

impl Eq for PowerOnRam

impl StructuralPartialEq for PowerOnRam